Lecturer: Dr. M. SamsamUniversity of Central Florida, Orlando,

Pictures from Platzer atlas and textbook

of human anatomy and K. Moore anatomy and Netter atlas of human anatomy

Bones and Muscles and regional anatomy of the upper limb part1

Bones of the upper limb:

Scapula:SurfacesBordersAnglesSpine of scapulaAcromion process13- glenoid cavity14- supraglenoid tubercle16- neck of scapula17- coracoid process18- Scapular notch

Clavicle:S shape, Medial 2/3 is convex anteriorly andlateral 1/3 is concave anteriorly.1- sternal end2- acromial end

SurfacesLower surface:5- costoclavicular impression6- conoid tubercle7- trapezoid line8- Costoclavicular ligament10- anterior sternoclavicular lig.11- interclavicular lig.14- Trapezoid ligament15- Conoid ligament

•Fractures of clavicle•Cleidocranial dysostosis

C- Sternoclavicular jointE- Acromioclavicular joint

Humerus:Has a shaft and 2 ends.

Proximal end: 1- head2- Anatomical neck8- Surgical neck3- Greater tubercle4- Lesser tubercle5- intertubercular sulcus 9- Deltoid tuberosity (lateral)11- medial border13- lateral border14- Sulcus for radial nerve (post. Surface)

Distal end:Condyles: 17- Trochlea, 18- capitulumEpicondyles: 15- medial, 16- lateral19- Radial fossa20- Coronoid fossa21- Sulcus for Ulnar nerve22- Olecranon fossa

*Fractures of the Humerus:

*Fractures of the surgical neck: injury to the Axillary nerve.

*Fractures of the middle of the shaft: may cause injury to the radial nerve: Wrist drop

•Fractures of the distal end of humerus: injury to the Median nerve.

•Fractures to the medial epicondyle: injury to the ulnar nerve.

*Traumatic separation of the proximalepiphysis under 18-20 years. Also in younger children since the capsule is stronger.

* Dislocation of the shoulder joint

Radius and Ulna bones

Radius:1- Body, 2- Head, 3- Articular fovea4- Articular circumference5- Neck 6- Radial tuberosity7- Interosseous margin8- Anterior surface, 9- Ant. Margin, 10- Lat. surface11- Post. Margin, 12- Post. Surface13- Pronator tuberosity, 14- Styloid process15- Ulnar notch, 16- Carpal articular surface17- Sulcus for tendon of Abd. Pollicis longus and ext. Pollicis brevis18- Sulcus for tendon of Ext. carpi radialis longus and brevis19- and 20-) sulci for Extensor pollicis longus, extensor digitorum and Ext. indicis.21- Dorsal tubercle

Radius and Ulna bonesUlna:

22- Shaft of Ulna, 23- Olecranon process24- Trochlear notch, 25- Coronoid process26- Radial notch, 27- Ulnar tuberosity28- Supinator crest, 29- Interosseous margin30- Anterior surface, 31- Ant. Margin32- Medial surface, 33- Post. Surface34- Post. Margin, 35- Nutrient foramen36- Head of Ulna, 37- Articular circumference38- Styloid process

*Colles’ Fracture: fracture of the distal end of the radius, posterior displacement. Falling on hand with extended arm (eg.: falling on ice).May be accompanied by avulsion of ulnar styloid process.

Carpal Bones:

2 rows, each row has 4 bones

Proximal row:1- Scaphoid (largest in this row)2- Tubercle of scaphoid3- Lunate4- Triquetrum5- Articular facet for Pisiform6- Pisiform

Distal row:7- Trapezium8- Tubercle of trapezium9- Groove for flexor carpi radialis tendon10- Articular facet for first metacarpal bone11- Trapezoid12- Capitate (bigest in 2nd row)13- Hamate14- Hamulus (hook of Hamate)

*Scaphoid bone is the most frequent bone to fracture among the carpal bones.*Lunate is the most dislocated carpal bone.

LateralMedial

Carpal tunnel:

The 2 rows of the carpal bones producethe carpal groove which is concave anteriorly.

*Flexor Retinaculum:Is a double layer of membrane covering thecarpal groove anteriorly and produces thecarpal tunnel for transmission of flexor muscles and median nerve.

*Points of insertion of flexor retinaculum:Tubercle of scaphoid, pisiform, tubercle of Trapezium and hook of Hamate.

*Carpal Tunnel Syndrome:Compression to the median nerve in thetunnel due to hypothyroidism, rheumatoid arthritis, pregnancy, Amyloidosis etc.It is a very painful condition.

LateralMedial

Metacarpal and phalangeal bones:

1- Head of the metacarpal bone2- Body3- Base4- Styloid process of the 3rd metacarpal B.5, 6, 7- Phalanx (digital bones)8- Body9- Head or trochlea10- Base11- Tuberosity of distal phalanx

Sesamoid bones at 1st metacarpo-phalangeal J.

Brachial Plexus

Axillary region: (Pyramidal shape)Borders: Pectoralis Major, Latis dorsi, ribs andintercostal muscles, humerus and coracobrachialis

Atlas: only look at the items

Shoulder muscles inserted to Humerus:Dorsal group:(1-2)- Supraspinatus: Abductor of the arm, belongs to the rotator cuff muscle group.NN: Suprascapular N. (C4-C6)

(4-5)- Infraspinatus: Lateral rotator of the armbelongs to the rotator cuff muscle group. NN: Suprascapular N. (C5-C6)

(8-9)- Teres minor: Lateral rotator of the arm,Rotator cuff group, NN: Axillary (circumflex) N. C5-C6

Pathology: tendinopathy of supraspinatus (baseball), calcification, pain, tendon rupture >40 y and in younger people, avulsion of greater tub.

Rotator cuff function: help to maintain the stability of the shoulder joint.

11- Deltoid: Origin: 12: clavicular, 13: acromial, and 14: spinal parts. Insertion: Deltoid tuberosity.NN: Axillary N. (C5- C6).Function: Most important abductor of the arm up to 90 degree.Ant. Part: flexes (anteversion) the arm+ medial rotation of the armMiddle part: abducts the armPost. Part: extends (retroversion) + lateral rotation

(1-2)– Subscapularis M:Arm adduction and medial rotation,NN: Subscapular N. (C5,C6,C7)Insertion: lesser tubercle (3)Pathology: paralysis cause maximal lat. Rotation

Rotator cuff muscles: supra+ infra spinatus, teres minor and subscapularis

(9-10)- Teres major M:Arm adduction and medial rotation,NN: Lower subscapular N. (C6-C7) moore

12- Latissimus dorsi M: (coughing M)Origin:13:vertebral part, 14:thoracolumbar part,15:iliac part and 16:costal partInsertion: crest of the lesser tubercleFunction: Adduction and medial rotation and extension of the arm,NN: Thoracodorsal N. (C6, C7, C8).

Ventral Muscle group:

1- Coracobrachialis M:Origin: coracoid process (2).Insertion: medial surface of the humerusFlexion (anteversion) and adduction of arm,Musculocutaneous N. (C5,C6,C7).

4- Pectoralis Minor M:Origin: 3-5th ribsInsertion: coracoid processIt lowers and rotates the scapula,Medial pectoral N. (C8- T1).

7- Pectoralis major M: Origin: 8:clavicular part, 9:sternocostal part, 11:abdominal partInsertion: crest of the greater tubercle.F: Adduction and medial rotation of humerusNN: lateral and medial pectoral N.(C5-T1).l

Dorsal muscle groupSerratus anterior M:Origin: 1st-9th ribs (9-10-11-12-13)Insertion: From superior to inferior angle and the medial border of the scapula.Function:**Elevation of the arm over 90o

Protracts the scapula and holds it against the thoracic wall and rotates thescapula laterally to elevate the arm**Long thoracic N. (C5- C6- C7)**Paralysis: Winged scapula: lifting the arm beyond 90o is not possible Differential diagnosis: Rhomboid M injury,Here you have winged scapula as well, but arm elevation is normal.1 and 4 in A are Rhomboid muscles

Ventral muscle group

Subclavious M: Number 1 (blue)Origin: 1st ribInsertion: sulcus for the subclavian muscle on the lower surface of clavicle. F: it pulls the clavicle towards the sternumNerve to the Subclavious (C5- C6)

2-4) Omohyoid muscle

Cranial muscle inserted on the Shoulder girdle:

6- Trapezius M11- Sternocleidomastoid M

Muscles of the armBiceps M (4):

Origin: coracoid process (8) and supraglenoid tubercle (6).Insertion: Radial tuberosity (9) and forearm fascia.

Acts on 2 joints:Long head (5): abductor and medial rotatorof the armShort head (7): adductor of the armBoth heads flex (anteroversion) shoulder jointOn elbow joint: flexor and strong supinator ofthe forearm.NN: Musculocutaneous N. (C5- C6)**Biceps Jerk: C5- C6

Brachialis M (1):Origin: distal half of humerus anteriorly (2)Insertion: ulnar tuberosity (3)/ coronoid process.Powerful flexor of the elbow jointNN: Musculocutaneous N. (C5- C6)and radial nerve to some of its lateral part

Coracobrachialis M (repeated):Origin: coracoid process. Insertion: medial surface of the humerusFlexor of the arm. Musculocutaneous N. (C5,C6,C7).

Triceps M:

Has 3 heads.Long head (2) originates from infraglenoid tubercle (5).Lateral and medial heads originate from humerusInsertion: Olecranon processFunction: Chief extensor of elbow jointLong head acts on 2 joints:Retroversion and adduction of the armRadial N. (C6- C7- C8)Triceps Jerk: C7- C8

Anconeus M:Assists tricepsRadial N.(C7- C8- T1)

Plexus syndromes and mononeuropathies (the upper limb)

Upper brachial plexus lesion: Erb-Duchenne paralysis (C5-C6):

Traction on the arm at birth or falling on the shoulder may damage the upper part of the plexus (roots may be pulled out of spinal cord)

Signs: Deltoid and supraspinatus are paralyzed (no arm abduction)

Infraspinatus paralysis leads to medial rotation of the arm.

Biceps and Brachialis are also paralyzed (no elbow flexion) .

Loss of Biceps and supinator (weak supination)

Adductors of shoulder are mildly affected (pectoralis major and Latissimus dorsi)

Plexus syndromes and mononeuropathies (the upper limb)

• Lower brachial plexus lesion:

Not as common as upper plexus injuries. Paralysis of the intrinsic muscle of hand (small muscles) with

anesthesia. Results from sudden upward pull of the shoulder.

Klumpke’s paralysis (C8-T1): Injury to C8-T1 roots following forced

abduction of the shoulder.

Signs: Atrophic paralysis of the forearm and small muscles of hand (Claw hand) and often a sympathetic palsy: eg: a Horner’s syndrome

Damage to axillary nerve

Ventral Forearm Muscles: Superficial layer:1- 4) Pronator TeresHumeral and ulnar headsFunction: pronation of forearm and flexionat elbowNN: Median N. (C6- C7)

14- Palmaris longusFlexes the hand toward the palm, tenses the palmar aponeurosis, Median N. (C7-C8)15- Palmar Aponeurosis

12- 13) Flexor carpi radialisRuns in the carpal canal in a groove on trapezium.F: Palmar flexion and Radial abduction of handNN: Median N. (C6- C7)

5-10) Flexor digitorum superficialisStrong flexors of the finger (4 medial) joints; also flexes the wrist , Runs in the carpal tunnelNN: Median N. (C7, C8, T1)

16- Flexor carpi ulnaris Humeral and Ulnar (from Olecranon) heads.F: Hand (palmar) flexion and adductionRuns outside of carpal tunnel. NN: Ulnar N. (C7- C8)18- Pisiform bone

Ventral Forearm Muscles: Deep layer

4-6) Flexor digitorum Profundus Runs through the carpal tunnelFunction: it is a flexor of the wrist, midcarpal, metacarpophalangeal and phalangeal jointsNN: Median N. (ant. Interosseous branch) laterally (C8 and T1), Ulnar N. medially (C8- T1)

8- 10) Flexor pollicis longusRuns through the carpal tunnelHas it’s own tendon sheathFlexor of the terminal phalanx (thumb)NN: Median N. (ant. Interosseous branch) C8- T1

1- 3) Pronator quadratusPronates the forearm (with Pronator Teres)Median N. (ant. Interosseous branch) C8- T1

Carpal tunnel:

Produced by flexor retinaculum (9) overthe carpal bones anteriorly.

*Structures passing into the tunnel:Flexor digitorum superficialis (12) and profundus,Flexor pollicis longus (11) and Median nerve.Flexor carpi radialis (10) has its own canal in thegroove of trapezium.

*Carpal Tunnel Syndrome:Compression to the median nerve in thetunnel due to hypothyroidism, rheumatoid arthritis, pregnancy, Amyloidosis etc.It is a very painful condition.

Palmarcarpal tendon sheaths (green)

Forearm Muscles: Radial group

7-9) Brachioradialis (beer drinking M.)It brings the forearm into midposition betweenpronation and supination; in this position it actsas a flexor (forearm flexor)NN: Radial N. (C5- C6 and C7)

4-6) Extensor carpi radialis longusExtensor and abductor of hand at wrist jointNN: Radial N. (C6- C7)

1-3) Extensor carpi radialis brevisExtensor and abductor of the hand at wrist jointNN: Radial N. (deep branch) (C7- C8)

Elbow tendinitis (lateral epicondylitis) or(tennis/golfer’s elbow): periosteal irritation, pain

10- Extesor digitorum11- Ext. digiti minimi12- Ext. carpi ulnaris13- Ext. pollicis longus14- Ext. pollicis brevis15- Abductor pollicis longus16- Ulna17- Radius

Dorsal Forearm MM: superficial layer

1-3) Extensor digitorumRuns in 4th tendon compartment.Produces the dorsal aponeurosis (3) withintertendinous connections (5)Function: Extends the 4 medial fingers (metacarpophalangeal J.), strong dorsiflexor of the hand at wrist jointNN: Post. Interosseous branch of deep radial nerve C7- C8

6- Extensor digiti minimiRuns in the 5th tendon compartmentExtension of the 5th digit and dorsiflexion of handNN: Post. Interosseous branch of deep radial nerve C7- C8

7-8) Extensor carpi ulnarisRuns in the 6th tendon compartmentCommon head and ulnar head originInserted to the base of 5th metacarpalExtends and adducts the handsNN: Post. Interosseous branch of deep radial nerve C7- C8

Deep layer of dorsal forearm muscles:1-4) SupinatorEncircles the radius and supinates forearmNN: Deep branch of radial N. C5- C6

5-9) Abductor pollicis longusRuns through 1st tendon compartmentAbduction of the first thumb+ it’s extensionat carpometacarpal joint

10-14) Extensor pollicis brevisRuns in the 1st tendon compartmentExtension of the proximal phalanx at metacarpophalangeal joint.

15-18) Extensor pollicis longusRuns through 3rd tendon compartmentExtends the thumb using the crest on radius as a fulcrum (at metacarpophalangeal andInterphalangeal joints).

19-21) Extensor indicisRuns through 4th compartment with Ext. digitorumIndex extension and hand dorsiflexion

All 4 muscles above are innervated by:Post. Interosseous branch of deep radial nerve C7- C8

Extensor retinaculum (1):Covers the carpal bones dorsally and hasseptae which produce 6 tendon compartments through which tendon ofthe extensor muscles and the abductor pollicis longus pass. Dorsal tendon sheaths (green) Palmarcarpal tendon sheaths (green)

Thenar Muscles:

1- Abductor polloicis brevis:Origin: scaphoid tubercle and Flexor retinaculumInsertion: radial sesamoid and proximal phalanxAbduction of thumb, Median N. C8-T1

6-7) Flexor pollicis brevis:Origin: superficial head from flexor retinaculum (3)deep head from trapezium (8), tarpezoid (9) and capitate (10) Insertion: sesamoid bone of metacarpophalangeal J.Flexes the thumbSuperficial innervation by median N. C8-T1Deep head by ulnar N. C8-T1 (not in Moore)

Adductor Pollicis: 2 headsTransverse head (11) origin: 3rd metacarpal boneOblique head: from capitate and other carpal and 2nd/3rd metacarpals Inserted into ulnar sesamoid bone (14).Thumb Adduction. Deep branch of Ulnar nerve C8-T1

Opponens pollicis (15) :Origin: tubercle of trapezium (16) and flexor retinaculum (3).Insertion: radial margin of 1st metacarpal bone. Thumb opposition. Median N. C8- T1

Palmar AponeurosisConsists of Longitudinal (1) and transverse (2)Fascicles. Reach the tendon sheath of flexors (3)and deep transverse metacarpal ligaments.Dupuytren’s contracture: progressive fibrosis, thickening and shortening of the aponeurosis leads to partial flexion of the ring and small finger.

Palmaris brevis in hypothenar eminence connect the skin of ulnar border to palmar aponeurosis and flexor retinaculum.Innervation: superficial branch of ulnar N. (C8- T1)

Hypothenar Muscles: All innervated by: deep branch of ulnar N. C8- T1Abductor digiti minimi (9)Origin: pisiform (12) pisohamate lig. (13), Flex. Ret (8)Insertion: base of proximal phalanx of 5th digitAbducts the 5th digit

Flexor digiti minimi (10)Origin: Flexor retinaculum and hamate hamulusInsertion: base of proximal phalanx of 5th digitFlexes the 5th digit

Opponens digiti minimi (11)Origin: Flexor retinaculum and hamate hamulusInsertion: Ulnar margin of 5th metacarpMakes opposition of the 5th finger to thumb possible

Muscles of the Metacarpus:

Interossei Muscles:Palmar interosseous, 3 sigle-headedDorsal interosseous, 4 double-headed

Palmar interossei (1): 3 musclesOrigin: 2nd, 4th and 5th metacarpalsInsertion: corresponding proximal phalangesand dorsal aponeurosisFunction: Adduction of digits, assist lumbricalsUlnar N. deep branch (C8-T1)

Dorsal Interossei: 4 musclesOrigin: adjacent sides of two metacarpsInsertion: base of the 2nd-4th proximal phalangesand dorsal aponeurosisFunction: Abduction of digitsUlnar N. (deep branch) C8- T1

Lumbricals: 4 muscles2 lateral (radial) and 2 medial (ulnar)Origin: tendon of flexor digitorum profundusInsertion: lateral sides of dorsal aponeurosis2 lateral ones innervated by Median N. C8-T12 medial ones innervated by Ulnar N. C8-T1