Skeletal Muscular systemObjectives

Know muscle

Group or compartment

Location

Function

Origin and insertion

Innervation

Synergists and antagonists

Skeletal Muscular systemvoluntary movements of body through space

includes skeletal striated muscle

every cell innervated (neuropathy or denervation atrophy)

(levels of severity: neurapraxia, axonotmesis, neurotmesis)

Origin – stationary point of muscle attachment

Slip – segmented origin

Insertion – affected point of muscle attachment

Gaster – muscle belly, contractile, muscular and connective tissues

Dense regular connective tissues

Tendon – dense regular connective tissue often used as origin or

insertion

Aponeurosis – flat, sheet-like tendon

Endomysium – invests muscle fibers (cells)

Perimysium – invests muscle fascicles

Epimysium or fascia – invests entire muscle gaster

or groups of muscles into compartments

Skeletal Muscular system

Synergist – muscles with similar function, usually in the same

compartment and with the same innervation

Antagonist – muscles with opposing function, usually in opposite

compartments and with different innervation, but sometimes

antagonists work synergistically

Facilitator or fixator – a muscle that stabilizes the origin of another

Intrinsic – located within the structure that is affected

Extrinsic – located outside the structure that is affected

Naming of muscles based on any combination of the following:

Shape – e.g., teres major, deltoideus, triceps, digastric

Location – e.g., brachialis, temporalis, popliteus, tibialis anterior

Function – e.g., supinator, rotatores

Origin and/or insertion – e.g., iliacus, subscapularis, flexor carpi ulnaris

Names of muscles are minimal, therefore potentially ambiguous

Flexor digitorum superficialis – antebrachium

Flexor digitorum longus – crus

Extensor digitorum longus – crus

Extensor digitorum communis – antebrachium

General rules of function and innervation by muscle groupCranial – cranial nerves

Cervical – cranial nerves (except vertebral axial muscles)

Visceral – nV, nVII, nIX, X

Epibranchial - nXI

Hypobranchial or “infrahyoid” – (Ansa Cervicalis: nXII and C1-C3)

Axial (postcranial, including cervical and trunk) – spinal nerves

Epaxial – dorsal rami

Hypaxial – ventral rami

Appendicular – definitive nerves via plexuses from ventral rami of spinal nerves

Ventral mass muscles (flexors, adductors, pronators) –

preaxial nerves or anterior divisions of plexus

Dorsal mass muscles (extensors, abductors, supinators) –

postaxial nerves or posterior divisions of plexus

Muscle groups and generalizationsAxial muscles – muscles that affect the axial skeleton

most both originate and insert on the axial skeleton

Head and Neck

Extrinsic ocular – muscles of ocular gaze, innervation by nIII, nIV, nVI

Intrinsic ocular – smooth muscle within eye, innervation by nIII

Muscles of mastication – insertion on mandible, innervation by nV (and ½

by nVII)

Muscles of facial expression – innervation by nVII

Intrinsic muscles of the tongue – within tongue, innervation by nXII

Extrinsic muscles of the tongue – move tongue relative to oral cavity,

innervation by nXII

Muscles of the styloid process (not a real group)

Muscles of floor of oral cavity (not a real group)

Muscles of soft palate – very small, assist in swallowing

Pharyngeal constrictors – assist in swallowing, innervation by nX

Muscles of the Larynx – innervation by recurrent laryngeal branch of nX

Epibranchial muscles – trapezius and sternocleidomastoid, innervation by

nXI

Hypobranchial (“Infrahyoid”) muscles – mostly small muscles of anterior

cervical region

innervation by Ansa Cervicalis (nXII, C1-C3)

Muscle groups and generalizationsAxial – Neck and torso, all muscles segmental

Epaxial – dorsal axial musculature, innervation by dorsal rami of spinal

nerves

Superficial layer – few and far between

Middle layer – long muscle fibers that diverge bilaterally superiorly

Deep layer – short muscle fibers that diverge bilaterally inferiorly

Hypaxial – ventral axial musculature, innervation by ventral rami of spinal

nerves

Cervical – scalene and longus muscles

Thoracic – three layers of intercostal muscles

Abdominal – three layers of abdominal oblique muscles plus rectus

abdominis

Diaphragms

Respiratory diaphragm

Pelvic diaphragm

Urogenital diaphragm

Appendicular musclesany muscle that affects a limb or its girdle – therefore (almost) any muscle that

inserts on a limb or its girdle, even if the origin is from the axial skeleton

always innervated by definitive nerves that arise from plexuses

several spinal nerves → plexus → several definitive nerves

Pectoral limb and girdle – brachial plexus

Pelvic limb and girdle – lumbosacral plexus (=lumbar and sacral plexuses)

appendicular muscles originating from axial skeleton are often segmented (slip)

superficial muscles usually travel across more joints than deeper muscles

Pectoral Limb and Girdle

Origin from torso

Anterior – pectoral flexors and adductors

(innervation cannot be generalized)

superficial – insert on scapula and humerus

deep – insert on scapula and clavicle

Posterior – pectoral extensors and abductors

(innervation cannot be generalized)

superficial insert on scapula and humerus

deep – insert on scapula

Rotator cuff – humeral rotators

anterior – 1 medial rotator, i.e., subscapularis muscle

innervated by subscapular nerve

posterior – 3 lateral rotators

(innervation cannot be generalized)

Pectoral Limb and Girdle

Brachium

Anterior – brachial and antebrachial flexors, adductor

all innervated by musculocutaneous nerve

Superficial – one muscle traverses two joints

Deep – muscles traverse one joint

Posterior – brachial and antebrachial extensors, abductor, rotator

(innervation cannot be generalized)

Pectoral Limb and Girdle (cont’d)

Antebrachium

Anterior – flexors and pronators

innervation by median nerve (and 1½ by ulnar nerve)

Superficial – origin from medial epicondyle of humerus

Deep – origin within antebrachium

Posterior – extensors and supinators

all innervated by radial nerve

Superficial

origin from supracondylar crest of humerus

origin from lateral epicondyle of humerus

Deep – origin from within antebrachium

insertion on pollex (except 1)

Manus

Thenar – muscles of the pollex

innervation by median nerve

Hypothenar – muscles of digiti minimi

innervation by ulnar nerve

Interossei – originate from metacarpals

innervation by ulnar nerve

Pectoral limb and girdleMajor branches of brachial plexus (from spinal nerves C5 – C8, T1)

Dorsal Scapular nerve – rhomboid muscles

Suprascapular nerve – rotator cuff

Subscapular nerve – subscapularis and teres major (medial brachial rotators)

Long Thoracic nerve – serratus anterior

Thoracodorsal nerve – latissimus dorsi

Medial and Lateral Pectoral nerves – pectoralis major and minor

Axillary nerve – deltoideus and teres minor

Radial nerve – triceps and posterior antebrachium

Musculocutaneous nerve – anterior brachium

Median nerve – anterior antebrachium and thenar

Ulnar nerve – 1½ medial antebrachial muscles, hypothenar, interossei

Pelvic Limb and GirdleOrigin from torso

Anterior – iliopsoas group, abdominal flexors of the femur

insert on lesser trochanter

innervation by femoral nerve

Posterior

superficial – gluteal group, femoral extensors and abductors

origin from false pelvis

innervation by gluteal nerves

deep – femoral rotators

origin from true pelvis and sacrum

Pelvic Limb and GirdleFemur

Anterior – quadriceps and sartorius, crural extensors

all innervated by femoral nerve

Posterior – ‘hamstrings’ muscles, femoral extensors and crural flexors

origin from ischial tuberosity (except ½)

innervation by tibial nerve (except ½)

Medial – femoral adductors

origin from true pelvis

most insert on linea aspera

all innervated by obturator nerve

Pelvic Limb and Girdle (cont’d)

Popliteal

origin from lateral condylar region of femur

Crus

Anterior – pedal dorsiflexors and invertor, digital extensors

all innervated by deep peroneal nerve

Lateral – pedal evertors

all innervated by superficial peroneal nerve

Posterior

all innervated by tibial nerve,

Superficial (sural) – pedal plantarflexors

all insert on calcaneus

Deep – pedal plantarflexor and invertor, digital flexors

1:1 antagonists of anterior crural muscles

Pes

Dorsum

digital and pedal extensors

all innervated by terminal branch of deep peroneal nerve

Plantar

digital flexors, adductors, and abductors

all innervated by terminal branches of tibial nerve

Pelvic limb and girdleMajor branches of lumbar plexus (from spinal nerves L2 – L4 )

Obturator nerve – medial femoral

Femoral nerve – iliopsoas and anterior femoral

Major branches of sacral plexus (from spinal nerves L4 – L5, S1 – S3)

Superior and Inferior Gluteal nerves – gluteal group

Sciatic nerve

Tibial nerve (or its branches) – posterior femoral (except ½) and

posterior crural, plantar pes

[Common] Peroneal Peroneal nerve – ½ posterior femoral

Deep Peroneal (or its branches) – anterior crural, dorsum pedis

Superficial Peroneal –lateral crural

And now onto the detailed muscle descriptions…

Muscles of the Orbit6 Extrinsic ocular muscles

muscles of ocular gaze

4 rectus muscles – “straight” muscles

Superior – elevation

Medial – adduction and convergence

Lateral – abduction and divergence

Inferior – depression

2 oblique muscles

Superior – rotation (intorsion), depression, abduction

Inferior – rotation (extorsion), elevation, abduction

Levator palpebrae superioris (orbital but not extrinsic ocular)

all innervated by nIII oculomotor except:

Superior ocular oblique – nIV trochlear nerve

Lateral ocular rectus – nVI abducens nerve

Ptosis – drooping eyelid, deficit of nIII (midbrain nucleus)

Ophthalamoparesis – inability to direct ocular gaze, as in

inability to abduct eye, deficit of nVI (hindbrain nucleus)

Muscles of mastication Mandibular adductors/elevators

all innervated by nV3 mandibular branch of trigeminal

Temporalis

mandibular adductor and retractor

Origin from temporal fossa and line

Inserts on coronoid process

Masseter

mandibular adductor and protractor

Origin from zygomatic arch

Inserts on lateral mandibular ramus and angle

Medial Pterygoideus

lateral mandibular movement

Origin from medial pterygoid plate of sphenoid

Inserts on medial mandibular ramus

Lateral Pterygoideus

mandibular protraction

Origin from lateral pterygoid plate of sphenoid

Inserts on superior medial mandibular ramus

Muscles of masticationMandibular abductor/depressor

Digastric

Posterior belly

Origin from mastoid notch

Innervation by nVII facial nerve

Central tendon

passes thru trochlea of lesser cornu of hyoid

Anterior belly

Inserts on posterior mandibular symphysis

Innervation by nV3 mandibular branch of trigeminal nerve

Muscles of facial expressionAll innervated by nVII facial nerve

Platysma – covers anterior cervical region

Occipitofrontalis or epicranius – supports scalp

Frontalis

Galea aponeurotica

Occipitalis

Buccinator – lines lateral oral cavity

Orbicularis oculi – ring around orbit

Orbicularis oris – ring around mouth

Zygomaticus major and minor

Levator anguli oris

Depressor anguli oris

Risorius – the smiling muscle

Bell’s palsy – facial muscle paralysis, drooping face, deficit of nVII

Intrinsic muscles of the tonguewithin tongue, affect the shape of tongue

Innervation by nXII hypoglossal nerve

Longitudinal fascicles

Transverse fascicles

Vertical fascicles

(major) Extrinsic muscles of the tonguemove tongue relative to oral cavity

Innervation by nXII Hypoglossal nerve

Genioglossus

lingual protractor

Origin from mandibular symphysis

Styloglossus

lingual retractor and elevator

Origin from styloid process of temporal

Hyoglossus

lingual retractor and depressor

Origin from body and greater cornu of hyoid

Muscles originating from styloid process of temporal boneListed from anterior to posterior:

Styloglossus (extrinsic muscle of the tongue)

Stylohyoideus

elevates hyoid during swallowing

Insertion on greater cornu of hyoid, nearest lesser cornu

bifurcates around central tendon of digastric

Stylopharyngeus

elevates larynx during swallowing

Insertion on thyroid cartilage of larynx

Muscles of soft palatesmall muscles that assist in swallowing

Tensor veli palatini – opens pharyngotympanic tube (Eustachian

canal)

Levator veli palatini

Salpyngopharyngeus

Uvulus

Pharyngeal constrictors muscles that circle the pharynx and assist in swallowing

Innervation by vagus nerve

Superior constrictor

Middle constrictor

Inferior constrictor

Intrinsic Laryngeal Musclessmall muscles that control vocal cords and speech

Innervation by recurrent laryngeal branch of nX vagus nerve

Arytenoideus

Muscles of floor of oral cavitylisted from superior to inferior or deep to superficial

Genioglossus (extrinsic muscle of the tongue)

Geniohyoid

Origin from posterior mandibular symphysis

Insertion on body of hyoid

Innervation by Ansa Cervicalis

Mylohoid

Origin from mylohyoid line of medial mandibular body

Insertion on body of hyoid

Innervation by branch of nV3 Mandibular Nerve

Anterior belly of digastric (muscle of mastication, nV3)

Platysma (muscle of facial expression, nVII)

Hypobranchial or “Infrahyoid” musclessmall segmental muscles of anterior cervical region extending from

pectoral girdle to mandible

Innervation by Ansa Cervicalis

roots from nXII Hypoglossal nerve and spinal nerves C1-C3

Sternothyroideus

Origin from manubrium deep and medial to sternohyoid

Inserts on thyroid cartilage of larynx

Sternohyoideus

Origin from manubrium superficial and lateral to sternothyroid

Insertion on hyoid lateral to thyrohyoid, medial to omohyoid

Thyrohyoideus

Origin from thyroid cartilage of larynx

Insertion on body of hyoid (somewhat laterally)

Omohyoideus

Origin from superior margin of scapula

Restrained by fascia of clavicle

Insertion on greater cornu of hyoid lateral to sternohyoid

Epibranchial musclesInnervation by nXI spinal accessory nerve

Trapezius

cranial and cervical extensor

scapular elevator, depressor, and rotator (inferior angle laterally)

Origins: superior nuchal line, nuchal ligament, spines of all

thoracic vertebrae

Insertion on scapular spine, acromion, and lateral 1/3 of clavicle

superficial to latissimus dorsi where they overlap (T7-T12)

deficit - inability to abduct brachium above horizontal (same as deficit of

serratus anterior muscle or long thoracic nerve)

Sternocleidomastoid

cranial and cervical flexor and rotator

Inserts on mastoid process of temporal bone

Sternomastoid

Origin from manubrium

Cleidomastoid

Origin from sternal extremity of clavicle

Triangles of the neckPosterior triangle

Superior belly of the trapezius, sternocleidomastoid, and clavicle

Anterior triangle

Sternocleidomastoid, inferior margin of the mandible, and

midsagittal plane

Submandibular or submaxillary triangle

Inferior margin of mandible and anterior and posterior bellies of

the digastric

Carotid triangle

Posterior belly of the digastric, superior belly of the omohyoid,

and sternocleidomastoid

Superficial layer of Epaxial MusclesInnervation by dorsal rami of spinal nerves

Splenius (capitis and cervicis) – the “bandage”

cranial and cervical extensor

(unilaterally a “lateral flexor”)

deep to superior part of trapezius

Origin from nuchal ligament and spines of cervical and uppermost

thoracic vertebrae

Inserts on transverse processes of cervical vertebrae, lateral superior

nuchal line and mastoid processes

Serratus posterior superior

costal elevator

Origin from lower cervical and upper thoracic vertebrae

Inserts on costae 2 thru 5

Serratus posterior inferior

Costal depressor

Origin from lower thoracic and upper lumbar vertebrae

Inserts on costae 9 thru 12

Middle layer of Epaxial Muscleslong muscle fibers that diverge laterally superiorly

Innervation by dorsal rami of spinal nerves

Erector spinae

Listed from lateral to medial:

Iliocostalis

Origin from sacrum and iliac crest

Inserts on costae and transverse processes of cervical vertebrae

Longissimus

Origin from sacrum and transverse processes

Inserts on transverse processes and costae

Spinalis

Both originates and inserts on spinous processes

Deep layer of Epaxial Musclesshort muscle fibers that diverge laterally inferiorly

Innervation by dorsal rami of spinal nerves

Transversospinalis

Origin from transverse process

Inserts on spinous process of superior vertebrae

Listed from lateral to medial, superficial to deep:

Semispinalis

Fascicles travel 6 vertebrae

Multifidis

Fascicles travel 4 vertebrae

Long rotatores

Fascicles travel 2 vertebrae

Short rotatores

Fascicles travel 1 vertebra

Deep layer of Epaxial Muscles (cont’d)

Levators costarum

Origin from transverse processes

Inserts on angle of inferior costae

Long

Short

Quadratus lumborum

Forms posterior wall of abdominal cavity

Origin from iliac crest

Inserts on lumbar transverse processes and 12th costa

Hypaxial musclesInnervation by ventral rami of spinal nerves

Hypaxial muscles of Cervical Region

Scalene muscles

Cervical flexors and rotators

Insertion on transverse processes of cervical vertebrae

Anterior scalenus

Origin from costa 1

Middle scalenus

Origin from costa 1

Posterior scalenus

Origin from costa 2

Relationships of Scalene Muscles to Major Structures

Anterior to Scalenus Anterior:

Carotid Sheath, contents:

Common Carotid Artery

Internal Jugular Vein

Vagus Nerve (nX)

Phrenic Nerve

Subclavian Vein

Between Anterior and Middle Scalenus

Subclavian Artery

Roots of Brachial Plexus

Hypaxial muscles of Cervical Region (cont’d)

Longus muscles

Origin from cervical vertebrae

Longus colli

Cervical flexors and rotators

Insertion cervical vertebrae

Longus capitis

Cranial flexor

Inserts on occipital bone

Hypaxial muscles of Thorax

External intercostal

Fibers oriented inferomedially

Internal intercostal

Innermost intercostal

Rectus thoracis (occasional)

Transversus thoracis

internal to thoracic cage

Hypaxial muscles of abdomen3 abdominal oblique muscles

equivalent to intercostal muscles

Origins from lower costae, lumbar vertebrae, iliac crest, and

inguinal ligament

Insert on linea alba via aponeuroses

External abdominal oblique

Aponeurosis forms superficial layer of rectus sheath

Internal abdominal oblique

Aponeurosis splits to form superficial and deep layers

of rectus sheath

Transversus abdominis

Aponeurosis forms deep layer of rectus sheath

Rectus abdominis – “straight muscle”

Contained within rectus sheath

Segmented by tendinous intersections

Origin from superior pubis

Inserts on costal cartilages 5 thru 7

Respiratory diaphragmInhalation

separates thoracic and abdominal cavities

Innervation by left and right phrenic nerves from spinal nerve C4

(and occasionally C3 or C5)

Origin from costal margin

Insertion on central tendon

Foramina for passage of structures

Esophageal hiatus – for esophagus

Aortic hiatus – for descending aorta

Caval hiatus – for inferior vena cava

paired Arcuate ligaments (lateral retinacula) – for psoas minor

muscles

Pelvic diaphragmforms floor of pelvic cavity

Levator ani

Puborectalis – the rectal sling

maintains continence

Pubococcygeus – medial

Iliococcygeus – lateral

Urogenital diaphragmSuperficial or inferior to pelvic diaphragm

Anterior to ischial tuberosities only

perforated by vagina and urethra

Pectoral Limb and Girdle - Origin from torsoAnterior superficial

Pectoralis major

Brachial flexor

Antagonist: latissimus dorsi

Origin: proximal 2/3’s clavicle, sternum, and costae

separated from deltoideus by deltopectoral triangle –

which is penetrated by cephalic vein

Insertion: proximal anterior humerus distal to greater tubercle

Innervation: medial and lateral pectoral nerves

Serratus anterior

Holds scapula onto thorax, scapular rotator and protractor

Synergist: trapezius in scapular rotation

Origin: most costae

Insertion: vertebral border of scapula, especially inferior angle

Innervation: long thoracic nerve, deficit characterized by “winged

scapula” and inability to abduct brachium above horizontal

deltopectoral triangle and cephalic vein

Pectoral Limb and Girdle - Origin from torsoAnterior deep

Pectoralis minor

Scapular protractor

Antagonists: rhomboid muscles

Origin: costae 3 thru 5

Insertion: coracoid process of scapula

Innervation: lateral pectoral nerve

Subclavius

Clavicular depressor

Origin: costa 1

Insertion: inferior medial clavicle

Pectoral Limb and Girdle - Origin from torsoPosterior superficial, proximal

Trapezius (really an epibranchial muscle)

Latissimus Dorsi

Humeral extensor

Antagonist: pectoralis major

Origins (simplified): thoracolumbar fascia of iliac crest, median sacral

crest, and spines of all lumbar and thoracic vertebrae 7 thru 12

(also a few costae and inferior angle of scapula)

Deep to trapezius where they overlap

Insertion: proximal anterior humerus immediately medial to pectoralis

major

Innervation: thoracodorsal nerve

Pectoral Limb and Girdle - Origin from torsoPosterior deep scapular elevators, retractors, rotators

all insert on vertebral border (medial margin) of scapula

listed from superior to inferior:

Levator Scapulae

Origin: nuchal ligament

Innervation: nerve to levator scapulae

Rhomboid muscles

Origin: spinous processes of C7-T4

Innervation: dorsal scapular nerve

Rhomboideus Minor – superior

Rhomboideus Major – inferior

Pectoral Limb and Girdle - Origin from torsoPosterior superficial, distal

Deltoideus

humeral abductor (primarily)

Origins: scapular spine and acromion and lateral 1/3 of clavicle

(just like insertion of trapezius and just unlike origin of

pectoralis major)

separated from pectoralis major by deltopectoral triangle

Insertion: deltoid tuberosity (lateral mid-diaphysis of humerus)

Innervation: axillary nerve (same as teres minor muscle)

Teres Major

humeral medial rotator and extensor/adductor

Origin: lateral margin of scapula inferior to teres minor

Insertion: anterior proximal humerus unlike teres minor

Innervation: subscapular nerve (like subscapularis)

separated from teres minor by long head of triceps (see

quadrangular space, after triceps)

Pectoral Limb and Girdle - Origin from torsoRotator cuff muscles

humeral rotators

responsible for integrity of glenohumeral joint

all originate from scapula

all insert on humeral tubercles

Humeral lateral rotators

all insert on greater tubercle

Listed from superior to inferior:

Supraspinatus

Origin: supraspinous fossa

Innervation: suprascapular nerve

Infraspinatus

Origin: infraspinous fossa

Innervation: suprascapular nerve

Teres Minor

Origin: inferolateral margin of scapula

Innervation: axillary nerve (like deltoideus muscle)

Separated from teres major by long head of triceps (see

quadrangular space, after triceps)

Pectoral Limb and Girdle - Origin from torsoRotator Cuff muscles - continued

humeral medial rotator

Subscapularis

Origin: subscapular fossa

Insertion: lesser tubercle

Innervation: subscapular nerve

Pectoral LimbBrachium

Anterior compartment – brachial and antebrachial flexors

Innervation by musculocutaneous nerve

Anterior Brachium, Superficial one muscle that completely traverses brachium without origin or

insertion on it

Biceps Brachii (not “biceps”)

brachial and antebrachial flexor

antagonist of triceps

2 Origins

Long head from supraglenoid tubercle, restrained in

intertubercular sulcus of humerus by transverse ligament

with synovial sheath

Short head from coracoid process

2 Insertions

Tendon of Biceps Brachii inserts on Radial Tuberosity

Bicipital Aponeurosis inserts on fascia of anterior

compartment of antebrachium

Anterior Brachium, Deep Innervation by musculocutaneous nerve

antagonists of triceps

two muscles that traverse only one joint each

Coracobrachialis

proximal

humeral flexor and adductor

Origin: coracoid process

Insertion: medial mid-diaphysis of humerus

Brachialis

distal

antebrachial flexor

Origin: distal diaphysis of humerus

Insertion: coronoid process of ulna

Posterior Brachium (cont’d)

Triceps (brachii)

antebrachial (and brachial) extensor

antagonist of anterior compartment brachial muscles

Insertion: olecranon process of ulna

Innervation: radial nerve (like all posterior compartment antebrachial

muscles)

3 Origins:

Long head

Origin: infraglenoid tubercle of scapula

passes between teres minor and teres major muscles

along with axillary nerve and circumflex humeral artery

Medial head

Origin: distal posterior diaphysis of humerus

deep to lateral head

Lateral head

Origin: proximal extremity of posterior humerus

superficial to medial head

Quadrangular Space

Boundaries

Medial – long head of triceps

Superior – teres minor

Lateral – surgical neck of humerus

Inferior – teres major

Contents

axillary nerve

circumflex humeral artery

Anterior Antebrachium, Superficial all but one muscle innervated by median nerve

all originate from medial epicondyle of humerus, most by common

tendon

central muscles insert more distally than more medial or lateral muscles

listed from lateral to medial:

Pronator teres

Insertion: proximal radius (anterior oblique line)

Flexor carpi radialis

carpal flexor and abductor

Insertion: pollical metacarpal

Palmaris longus - Superficial to flexor digitorum superficialis

palmar flexor

tendon anterior to flexor retinaculum, not within carpal tunnel

Insertion: palmar aponeurosis

Flexor digitorum superficialis - deep to palmaris longus

digital flexor

tendons bifurcate and insert on middle phalanges of digits II thru V

Flexor carpi ulnaris

carpal flexor and adductor

Insertion: pisiform

Innervation: ulnar nerve

Anterior Antebrachium, Deep

all originate within antebrachium

all but ½ innervated by median nerve

Flexor pollicis longus – lateral

Insertion: distal pollical phalanx

Flexor digitorum profundus – medial

four gasters corresponding to digits II thru V

tendons pass through bifurcation of tendons of flexor digitorum

superficialis

Insertions: distal phalanges of digits II-V

Innervation:

digits II and III by median nerve

digits IV and V by ulnar nerve

Pronator quadratus – deep to both of the above

oriented transversely

Origin: anterior distal ulna

Insertion: anterior distal radius

Posterior Antebrachium, Superficial all innervated by radial nerve

listed from lateral to medial:

2 muscles originating from supracondylar crest of humerus

Brachioradialis or supinator longus

supinator, flexor when antebrachium is already flexed

Insertion: distal radius

Extensor carpi radialis longus

carpal extensor and abductor

4 muscles originating from lateral epicondyle of humerus

Supinator or supinator brevis (origin also from proximal ulna)

Insertion: proximal radius next to pronator teres

Extensor carpi radialis brevis

carpal extensor and abductor

Extensor digitorum communis

Insertion: extensor expansion at metacarpophalangeal (MCP)

joint

Extensor carpi ulnaris

carpal extensor and adductor

Anconeus

antebrachial extensor

Posterior Antebrachium, Deep origins from within antebrachium

oriented obliquely

most insert on pollex

innervation by radial nerve

listed from medial to lateral (think posterior to lateral):

Supinator (also listed as superficial because of humeral head)

Extensor indicis

Extensor pollicis longus

Extensor pollicis brevis

Abductor pollicis longus

Palmar Manus(there are no intrinsic muscles of the dorsum of the manus)

Thenar muscles

intrinsic muscles of the pollex

Innervation: median nerve

Superficial

listed from lateral to medial (think lateral to anterior):

Abductor pollicis brevis

Flexor pollicis brevis

~Adductor pollicis (not a thenar muscle!)

Innervation by ulnar nerve!

Deep

Opponens pollicis

Hypothenar musclessimilar to thenar muscles but inserting on digit V

Innervation: ulnar nerve

Layers of the Palmar manuslisted from superficial to deep:

Palmar aponeurosis

Tendons of flexor digitorum superficialis

Insert on middle phalanges

Tendons of flexor digitorum profundus

Insert on distal phalanges

Interosseous muscles

Innervation: ulnar nerve

Insert on proximal phalanges

Palmar interossei

flexors and adductors

Dorsal interossei (palmar muscle compartment)

extensors and abductors

Intrinsic muscles of digits II-VLumbricals

Originate bilaterally from tendons of flexor digitorum profundus

Insert on extensor expansion

Peripheral nerve deficits, causes and symptoms Ape hand or papal hand

entrapment of median nerve at carpal tunnel or by pronator teres

atrophy of thenar muscles

lateral rotation of pollex, atrophy of thenar eminence

Claw hand

entrapment of ulnar nerve at cubital tunnel or Guyon’s canal

atrophy of adductor pollicis, hypothenar muscles, and lumbricals

abduction of digit V

flexion of digits IV and V

Drop hand

radial nerve deficit due to humerus fracture at spiral groove or lead

poisoning

flaccid flexion of carpus

Anterior muscles of pelvic girdle/limb originating from torso

lIiopsoas

abdominal flexors of the femur

common insertion on lesser trochanter

Innervation: femoral nerve

Iliacus

Origin: iliac fossa

Psoas major

Origin: lumbar vertebrae (transverse processes)

Psoas minor (variable)

Origin: lowermost costae (11 and 12)

passes thru arcuate ligaments or lateral retinacula of respiratory

diaphragm

Additional insertion on pectineal crest

Posterior muscles of pelvic girdle/limb originating from torsoGluteal group

pelvic extensors and abductors of the femur

all except gluteus maximus innervated by superior gluteal nerve

Gluteus maximus

femoral extensor, antagonist of iliopsoas

Origin: sacrum and posteromedial iliac crest

2 Insertions: gluteal tuberosity and iliotibial tract*

Innervation: inferior gluteal nerve

*Iliotibial tract inserts on anterior lateral tibial condyle

Posterior muscles of pelvic girdle/limb originating from torsoGluteal group (cont’d)

Gluteus medius

femoral abductor (stabilizes pelvis while walking) and medial rotator

antagonist of medial compartment muscles

antagonist of deep lateral femoral rotator muscles

Origin: lateral iliac crest deep to gluteus maximus posteriorly

Insertion: greater trochanter

Gluteus minimus

femoral abductor (stabilizes pelvis)

antagonist of medial compartment muscles

antagonist of deep lateral femoral rotator muscles

Origin: lateral iliac ala deep to gluteus medius

Insertion: greater trochanter

Tensor fasciae latae

locks knee in extended position (some rotation and abduction)

antagonist of popliteus

Origin: anterior iliac crest

Insertion: iliotibial tract

*Iliotibial tract inserts on anterior lateral tibial condyle

Deep lateral femoral rotators

Deep gluteal - listed from superior to inferior, as seen posteriorly:

Piriformis

Superior Gemellus

Tendon of Obturator Internus

Inferior Gemellus

Quadratus Femoris

not visible posteriorly (and not gluteal):

Obturator Externus

Deep lateral femoral rotators, by group

Muscle of greater sciatic foramen

Piriformis

Origin: sacrum (and iliac part of greater sciatic notch)

Insertion: greater trochanter

exits greater sciatic foramen superior to sciatic nerve (sciatic

nerve passes through piriformis in ~17% of population)

Obturator muscles

Obturator internus

Origin: posterior or internal side of bony margins of obturator

foramen and obturator membrane

Insertion: greater trochanter

Obturator externus

Origin: anterior or external side of bony margins of obturator

foramen and obturator membrane

Insertion: trochanteric fossa

deep to medial femoral compartment

tendon passes inferior to femoral neck

Deep lateral femoral rotators, by group (continued)

Muscles of lesser sciatic foramen

Superior gemellus

Inferior gemellus

Origins: lesser sciatic notch of ischium

Insertions: tendon of obturator internus

Tendon of obturator internus

Muscles of ischial tuberosity

Quadratus femoris

Origin: ischial tuberosity

Insertion: intertrochanteric crest

Anterior compartment femoral musclesinnervation by femoral nerve

antagonists of posterior compartment muscles

Sartorius

lateral femoral rotator, femoral and crural flexor

Origin: anterior superior iliac spine

Insertion: medial condyle of tibia

Quadriceps

crural extensor (and femoral flexor)

Insertion: patella (patellar ligament inserts on tibial tuberosity)

Rectus femoris

Origin: anterior inferior iliac spine

3 Vastus muscles

Origin: nearly the entire diaphysis of femur

Vastus medialis

Vastus intermedius

posterior or deep to rectus femoris

Vastus lateralis

Posterior compartment femoral muscles (“hamstrings”)femoral extensors and crural flexors

all but ½ originate from ischial tuberosity

all but ½ innervated by tibial nerve

Semimembranosus

medial

anterior to semitendinosus

Insertion: medial condyle of tibia

Semitendinosus

medial

posterior to semimembranosus

Insertion: tibia, proximomedial tibia, distal to medial condyle

Biceps femoris

lateral

Insertion: fibular head

Long head

Short head

Origin: linea aspera

Innervation: common peroneal nerve

Medial compartment femoral musclesfemoral adductors

all originate from anterior of true pelvis

most insert on linea aspera

all innervated by obturator nerve

Medial compartment, superficial or anterior

all originate from medial pubis except pectineus

listed from medial to lateral:

Gracilis

insertion: proximomedial tibia, distal to medial condyle

Adductor longus

Pectineus

superficial or anterior to adductor brevis

Origin: pectineal crest

Adductor brevis

deep or posterior to pectineus

Medial compartment femoral muscles, posterior or deep

Adductor magnus

Origin: inferior rami of pubis and ischium (below obturator

foramen)

Insertion: linea aspera and adductor tubercle

Adductor hiatus – distal foramen for passage of femoral artery

right anterior right posterior

Femoral triangleBoundaries:

Inguinal ligament

Sartorius

Adductor longus

location of femoral nerve, artery, and vein, and end of great or

long saphenous vein

Popliteal Fossaboundaries:

Semimembranosus, Semitendinosus

Biceps femoris

Medial and lateral heads of Gastrocnemius

location of popliteal artery, and end of short saphenous vein

Popliteal MusclesOrigin: posterior surface of lateral condyle of femur (but see below)

Innervation: tibial nerve

Plantaris

variably present, considered vestigial

superficial to popliteus

Tendon:

passes between gastrocnemius and soleus

emerges medial to Achille’s or calcaneal tendon

passes posterior to medial malleolus

Insertion: medial calcaneal tuberosity

Popliteus

medial tibial rotator, lateral femoral rotator, ‘unlocks’ knee

antagonist of tensor fasciae latae

deep to plantaris

Insertion: proximal posterior tibia (many consider origin and

insertion to be reverse of this since it is the femur that is

rotated)

Crus, posterior compartment, superficial (Sural muscles)Triceps surae

Plantarflexor

Antagonist of tibialis anterior and peroneus tertius

Insertion: calcaneal tuberosity via calcaneal or Achille’s tendon

Innervation: tibial nerve

Gastrocnemius

superficial

Medial head

Origin: medial epicondyle of femur

Lateral head

Origin: lateral epicondyle of femur

Soleus

deep

Origin: head of fibula (and posterior crest of tibia)

Crus, posterior compartment, deep all originate within crus

1:1 antagonists of anterior crural muscles

…but orientation of origins reversed

all tendons pass posterior to medial malleolus where they cross sides

and are restrained by the flexor retinaculum in the tarsal tunnel

all innervated by tibial nerve

listed from lateral to medial:

Flexor hallucis longus

tendon passes thru groove in calcaneus (posterior and inferior to

sustentaculum tali)

Tibialis posterior

most anterior or deepest

plantarflexor and invertor (synergistically with tibialis anterior,

antagonist of lateral compartment muscles)

invertor

Insertion: medial pes (navicular, cuneiforms, and metatarsal I-III)

Flexor digitorum longus

Crus, anterior compartmentall originate within crus

1:1 antagonists of deep muscles of posterior crus

all tendons restrained by extensor retinaculi anterior to both malleoli

all innervated by deep peroneal nerve

listed from medial to lateral:

Extensor hallucis longus

Tibialis anterior

anterior to all others

pedal dorsiflexor and invertor (synergistically with tibialis posterior,

antagonist of lateral compartment muscles)

Insertion: medial pes (cuneiform I and metatarsal I)

Extensor digitorum longus

Peroneus tertius

dorsiflexor

Insertion: metatarsal V

Crus, lateral or peroneal compartmenttwo evertors/plantar flexors (not peroneus tertius)

both originate from fibula

tendons pass posterior to lateral malleolus

both innervated by superficial peroneal nerve

Peroneus longus

Origin: fibular head and proximal fibula

tendon passes thru groove between cuboid and tuberosity of

metatarsal V

Insertion: medial pes (cuneiform II and metatarsal I, near tibialis

anterior)

Peroneus brevis

Origin: mid to distal fibula

Insertion: tuberosity of metatarsal V

Dorsum Pedisextensor hallucis brevis

extensor digitorum brevis (no equivalent muscle in manus)

Plantar Pessomewhat arbitrarily defined layers, listed from superficial to deep:

1st layer

plantar aponeurosis

2nd layer

abductor hallucis

flexor digitorum brevis (no equivalent muscle in manus)

inserts on digits II thru V

abductor digiti minimi

3rd layer

tendons of flexor digitorum longus

quadratus plantae or flexor accessorius

4th layer

flexor hallucis brevis

adductor hallucis (three heads: transverse, oblique, medial)

flexor digiti minimi

5th layer

interosseous muscles