Appendicular Appendicular SkeletonSkeleton

Pectoral (Shoulder) Girdle

Pectoral GirdleAttach the bones of the upper limbs to the axial skeletonConsist of two bones: clavicle and scapulaThe joints are freely movable in many directions

ClavicleAlso known as the collarboneLong, slender S-shaped bone that is horizontally above the first ribTransmits mechanical force from the upper limb to the trunk

ScapulaAlso known as the shoulder blade

Large, flat triangular bone situated in the posterior part of the thorax

A sharp ridge, the spine, runs diagonally across the back portion of the scapula bodyThe lateral end of the spine is the acromion, where the scapula articulates with the clavicle

The glenoid cavity is a depression inferior to the acromion. It articulates with the humerus head to form the shoulder joint.The coracoid process is where muscles attach.

Upper Limb

Upper LimbConsists of 30 bones (all paired up)Humerus in the armUlna and radius in the forearm8 carpals, 5 metacarpals, and 14 phalanges in the hand

HumerusLongest and largest bone of the upper limbArticulates with the scapula at the shoulder and both the ulna and radius at the elbow

UlnaLocated on the medial side of the forearm (pinky side)

Longer than the radius

RadiusLocated on the lateral side of the forearm (thumb side)

Proximal end consists of a head that articulates with the scapula’s glenoid cavity and an anatomical neck where the epiphyseal plate used to be

Humerus Bone Surface Markings

The body contains the deltoid tuberosity, a roughened V-shaped area where the deltoid muscle attaches

At the distal end, the capitulum articulates with the head of the radius.The radial fossa is a depression that receives the head of the radius when the forearm is bent.

The trochlea is a spool-shaped surface that articulates with the ulna.The coronoid fossa receives part of the ulna when the forearm is bent.The olecranon fossa is a depression on the back of the bone that receives the ulna when the forearm is straightened.

The olecranon forms the prominence of the elbow on the proximal end.The coronoid process along with the olecranon receives the trochlea of the humerus in the trochlear notch.

Ulna Bone Surface Markings

The radial notch is a depression for the head of the radius.

A styloid process is at the distal end.

Disc-shaped head at the proximal end articulates with the capitulum of the humerus and radial notch of the ulnaRadial tuberosity is a raised, roughened area that is where the biceps brachii muscle attaches to the bone

Radius Bone Surface Markings

The distal end of the radius articulates with three carpal bonesThere’s a styloid process at the distal end (similar to the ulna)

Carpus (Wrist)8 carpalsHeld together by ligaments with four bones in each rowNamed for their shapesShort bones

The carpals in the top row are the:

Scaphoid, Lunate, Triquetrum, and Pisiform

The carpals in the bottom row are the:

Trapezium, Trapezoid, Capitate, and Hamate

Metacarpus (Palm)5 metacarpalsEach consists of a proximal base, an intermediate body, and a distal headNumbered I-V starting with the thumbLong bones

Phalanges (Fingers)14 in each handThumb has two (proximal and distal)In each of the other four digits, there are three (proximal, middle, and distal)

Disorders of the Upper Limb

Carpal Tunnel Syndrome

Narrowing of the carpal tunnel causes compression of the median nerveThe nerve compression causes pain, numbness, tingling, and hand muscle weakness

Rotator Cuff InjuryTears or inflammation of ligaments and tendons of the shoulder near the humerusResults in pain and loss of shoulder mobility

Fractures

Checkpoint QuestionsWhich bones make up a pectoral girdle? What is the function of the pectoral girdle?With which part of the scapula does the humerus articulate?What part of the ulna is called the “elbow”?What part of which bones are commonly called the “knuckles”?What bones form the upper limb, from proximal to distal?