2024-Ch_14-15__3_
Introduction to the Upper Extremity (UE)
The UE includes the entire arm from the shoulder to the fingers.
The introduction covers the anatomy and functions with specific emphasis on the breast and pectoral region.
Author: Marlene Carmona, PT, DPT.
Pectoral Girdle
Anatomy
Also known as the shoulder girdle.
Comprised of the scapula and clavicle.
These bones articulate at the Acromioclavicular Joint (A/C joint).
Key Structures of the Upper Limb
Joint Capsule and Ligaments
Acromion of the scapula.
Clavicle, Coracoid process (of scapula).
Ligaments include:
Coracoclavicular ligament
Conoid ligament
Trapezoid ligament
Coraco-acromial ligament
Transverse humeral ligament
Sternoclavicular Joint
Articulation between the proximal end of the clavicle and the sternum.
Only bony point of contact between the UE and the axial skeleton (chest).
All other attachments are muscular.
Axilla
Also known as the armpit.
Fat-filled region between the chest wall and the UE.
Contains:
Brachial Plexus
Axillary Artery and Vein
Lymph Nodes
Division of the UE
Segments
Arm: Between the shoulder and elbow.
Forearm: Between elbow and wrist.
Hand: Joins forearm to wrist.
Functionality of the Upper Extremity
The UE is highly mobile.
Long bones supporting the UE include:
Humerus (Arm)
Radius (Forearm)
Ulna (Forearm)
Bones of the Hand
Carpals (8 wrist bones)
Metacarpals (5 palm bones)
Phalanges (14 finger bones)
Carpal Bones
Includes:
Scaphoid
Lunate
Triquetrium
Pisiform
Trapezium
Trapezoid
Capitate
Hamate
Scaphoid and Lunate articulate with the distal end of the Radius.
Phalanges Structure
Thumb: 2 (proximal and distal)
Digits 2-5: 3 each (proximal, middle, distal)
Hand Mobility
The hand can be considered a refined grasping and sensory organ.
Capable of two types of grasps:
Power grip: when a strong hold is needed.
Precision grip: for fine motor movements.
Muscles of the Upper Extremity
Compartments
Two main compartments: Anterior and Posterior.
Anterior compartment: Mainly flexors.
Posterior compartment: Mainly extensors.
Major Nerves of the UE
Brachial plexus supplies the UE.
Major terminal branches include:
Musculocutaneous
Median
Ulnar
Axillary
Radial
Cutaneous Innervation
Discussed differences with dermatomes.
Dermatomes Overview
Includes segmental innervation of the UE:
C2 & C3: Neck and back of the head.
C4: Upper chest, clavicle.
C5: Shoulder to elbow.
C6: Thumb and forearm.
C7: Middle finger.
C8: 4th and 5th fingers.
T1: Anterior and posterior forearm.
Arteries of the UE
Blood Supply
Main blood supply: Axillary Artery, changes to Brachial Artery.
Brachial artery divides into Radial and Ulnar arteries.
Vascular supply includes formation of deep and superficial palmar arches.
Veins of the UE
Structures
Deep veins follow arteries.
Major veins include:
Axillary vein
Subclavian vein
Superficial veins:
Cephalic vein
Basilic vein
Both connect through the Median cubital vein.
Clinical Correlations
Importance of understanding vascular anatomy, especially regarding breast masses and UE injuries.
Muscles of the Pectoral Region
Main Muscles
Pectoralis Major
Largest, fan-shaped muscle; adducts and medially rotates arm.
Pectoralis Minor
Stabilizes scapula, usually tight with poor posture.
Serratus Anterior
Abducts and protracts scapula; vital for UE movement.
Innervation of the Pectoral Region
Key Nerves
Supraclavicular Nerve: Sensory to superior pectoral region.
Intercostal Nerves: Sensory to inferior chest area.
Medial and Lateral Pectoral Nerves: Motor function to pectoral muscles.
Review of Conducted Materials
Suggested readings include analysis of osteology, clinical correlations, arterial and venous anatomy for further understanding of surgical implications in the UE.