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.