Upper Limb Anatomy Overview

Overview of Upper Limb Anatomy

• The upper limb consists of:
  • Shoulder
  • Arm (brachium)
  • Forearm (antebrachium)
  • Hand (manus)

Bones

1. Clavicle

   • Connects the upper limb to the trunk.
   • S-shaped bone; acts as a strut.

2. Scapula

   • Flat, triangular bone.
   • Forms the shoulder girdle with clavicle.
   • Major features: acromion, glenoid cavity, coracoid process.

3. Humerus

   • Long bone of the arm.
   • Features: head, neck, greater and lesser tubercles, shaft.

4. Radius

   • Lateral bone of the forearm (thumb side).
   • Involved in wrist joint.
   • Features: radial head, styloid process.

5. Ulna

   • Medial bone of the forearm (pinky side).
   • Forms the elbow joint with the humerus.
   • Features: olecranon, coronoid process, styloid process.

6. Carpals (8 bones)

   • Arranged in two rows (proximal and distal).
   • Major bones: scaphoid, lunate, pisiform, trapezium, trapezoid, capitate, hamate.

7. Metacarpals (5 bones)

   • Forms the framework of the palm.

8. Phalanges (14 bones)

   • Bones of the fingers.
   • Each finger has 3 (proximal, middle, distal), except the thumb which has 2.

Joints

1. Shoulder Joint (Glenohumeral)

   • Ball-and-socket joint.
   • Allows extensive range of motion.

2. Elbow Joint

   • Hinge joint between humerus, radius, and ulna.
   • Allows flexion and extension.

3. Wrist Joint (Radiocarpal)

   • Condyloid joint.
   • Allows flexion, extension, and lateral movement.

4. Interphalangeal Joints

   • Hinge joints between phalanges.
   • Permit flexion and extension.

Muscles

• Shoulder Muscles:

  • Deltoid: abduction of the shoulder.
  • Rotator Cuff Muscles: stabilize the shoulder joint.

• Arm Muscles:

  • Biceps Brachii: flexes elbow, supinates forearm.
  • Triceps Brachii: extends elbow.

• Forearm Muscles:

  • Flexors (anterior compartment): flex wrist and fingers.
  • Extensors (posterior compartment): extend wrist and fingers.

• Hand Muscles:

  • Thenar muscles: move the thumb.
  • Hypothenar muscles: move the little finger.
  • Intrinsic muscles: control fine motor movements.

Nerves

• Brachial Plexus:
  • Major nerve network providing motor and sensory innervation to the upper limb.
  • Main nerves: median, ulnar, radial, musculocutaneous.

Blood Supply

• Subclavian Artery:

  • Main artery supplying the upper limb.

• Brachial Artery:

  • Continuation of the axillary artery.

• Radial and Ulnar Arteries:

  • Supply blood to the forearm and hand.

Function and Mobility

• The upper limb is crucial for:
  • Grasping and manipulation.
  • Strength and endurance activities.
  • Coordination and fine motor skills.

Upper Limb Anatomy Overview

• The upper limb is composed of the shoulder, arm, forearm, and hand.
• The shoulder connects the upper limb to the trunk.
• The arm (brachium) is the segment between the shoulder and elbow.
• The forearm (antebrachium) is the segment between the elbow and wrist.
• The hand (manus) is the distal part of the upper limb.

Bones

• The clavicle, an S-shaped bone, acts as a strut connecting the upper limb to the trunk.
• The scapula is a flat, triangular bone forming the shoulder girdle with the clavicle.
• The scapula has key features: the acromion, glenoid cavity, and coracoid process.
• The humerus is the long bone of the arm, with features including the head, neck, greater and lesser tubercles, and shaft.
• The radius, located on the thumb side of the forearm, is involved in the wrist joint.
• The radius has features: radial head, and styloid process.
• The ulna, the medial bone of the forearm (pinky side), forms the elbow joint with the humerus.
• The ulna has features: olecranon, coronoid process, and styloid process.
• The carpals, eight small bones arranged in two rows, provide the framework for the wrist.
• The carpals include the scaphoid, lunate, pisiform, trapezium, trapezoid, capitate, and hamate.
• The metacarpals, five bones forming the palm, are the bones of the hand.
• The phalanges, 14 bones composing the fingers support the movements of the hand.
• Each finger has three phalanges (proximal, middle, and distal) except the thumb, which has two phalanges.

Joints

• The shoulder joint, a ball-and-socket joint, allows for extensive range of motion.
• The elbow joint, a hinge joint between the humerus, radius, and ulna, permits flexion and extension.
• The wrist joint, a condyloid joint, enables flexion, extension, and lateral movement.
• The interphalangeal joints, hinge joints between the phalanges, allow for flexion and extension.

Muscles

• Shoulder muscles:
  • The deltoid muscle abducts the shoulder.
  • Rotator cuff muscles stabilize the shoulder joint.
• Arm muscles:
  • The biceps brachii muscle flexes the elbow and supinates the forearm.
  • The triceps brachii muscle extends the elbow.
• Forearm muscles:
  • Flexors in the anterior compartment of the forearm flex the wrist and fingers.
  • Extensors in the posterior compartment of the forearm extend the wrist and fingers.
• Hand muscles:
  • Thenar muscles move the thumb.
  • Hypothenar muscles move the little finger.
  • Intrinsic muscles control fine motor movements.

Nerves

• The brachial plexus is a major nerve network providing motor and sensory innervation to the upper limb.
• The brachial plexus contains the median, ulnar, radial, and musculocutaneous nerves.

Blood Supply

• The subclavian artery is the main artery supplying blood to the upper limb.
• The brachial artery, a continuation of the axillary artery, supplies blood to the arm.
• The radial and ulnar arteries provide blood to the forearm and hand.

Function and Mobility

• The upper limb plays a crucial role in:
  • Grasping and manipulation of objects.
  • Strength and endurance activities.
  • Coordination and fine motor skills.