Overview
This lecture covers the bones and key anatomical features of the pectoral girdle and upper limb, including the clavicle, scapula, humerus, forearm bones (radius and ulna), and the bones of the hand.
Pectoral Girdle: Clavicle and Scapula
- The clavicle is the collarbone and serves as a simple strut for upper limb support.
- The scapula has important features: acromion (top/superior), coracoid process (just below acromion), inferior angle (lowest point), and medial border (long inside edge).
- Posterior view of scapula includes the spine (raised ridge), acromion (end of spine), coracoid process, and glenoid fossa (socket for arm bone/humerus).
Humerus: Features and Articulation
- The head of the humerus is the round, proximal end that fits into the glenoid fossa.
- Greater tubercle (lateral) and lesser tubercle (medial/anterior) are muscle attachment points.
- The intertubercular sulcus (groove) separates the tubercles.
- Deltoid tuberosity is the raised area on the shaft for deltoid muscle attachment.
- The distal humerus has medial and lateral epicondyles (widened, rounded areas above the elbow joint).
- The capitulum (lateral) articulates with the radius; the trochlea (medial) articulates with the ulna.
Forearm: Radius and Ulna
- Radius (lateral, thumb side) and ulna (medial, pinky side) are connected by the interosseous membrane.
- Head of the radius is proximal and articulates with capitulum; radial tuberosity is just below the head.
- Styloid process is at the distal end of the radius.
- Ulna has a large proximal olecranon (elbow), articulating with the trochlea.
- The styloid process is at the ulna's distal end; the head is also distal (opposite of radius).
Bones of the Hand
- Carpal bones form the wrist and provide stability while allowing movement.
- Metacarpals are the long bones of the palm.
- Phalanges are finger bones: 3 in each finger (proximal, middle, distal) and 2 in the thumb.
Key Terms & Definitions
- Acromion — Highest point of the scapula.
- Coracoid process — Anterior projection of the scapula below the acromion.
- Glenoid fossa — Socket in the scapula for the humerus head.
- Tubercle — Small rounded projection for muscle attachment.
- Epicondyle — Rounded area above a joint's condyle.
- Capitulum — Lateral, rounded articular surface on the humerus.
- Trochlea — Medial, spool-shaped articular surface on the humerus.
- Interosseous membrane — Fibrous sheet connecting radius and ulna.
- Olecranon — Prominent elbow projection of the ulna.
- Carpals — Wrist bones.
- Metacarpals — Palm bones.
- Phalanges — Finger bones.
Action Items / Next Steps
- Review anatomical diagrams to identify each bone and feature discussed.
- Prepare for next lecture on the pelvic girdle and lower limb.