Comprehensive guide to the bones, joints, and muscles of the shoulder, arm, forearm, and hand with training relevance for calisthenics.

Upper Extremity Anatomy: Complete Guide to Structure and Function

The upper extremity, comprising the shoulder, arm, forearm, and hand, is a marvel of anatomical engineering that enables an incredible range of movements essential for daily activities and athletic performance. For calisthenics athletes, understanding upper extremity anatomy is crucial for optimizing training, preventing injuries, and mastering advanced movements like handstands, planches, and muscle-ups.

What is the Upper Extremity?

The upper extremity refers to the entire upper limb, extending from the shoulder girdle to the fingertips. This complex anatomical region consists of multiple bones, muscles, joints, and soft tissues working in harmony to provide:

Range of Motion: The upper extremity offers the greatest range of motion of any body region, with the shoulder joint alone capable of movement in multiple planes
Strength and Power: Essential for pushing, pulling, lifting, and supporting body weight
Fine Motor Control: Enables precise movements required for grip, manipulation, and skill execution
Stability: Provides a stable base for transferring force from the trunk to the hands

The upper extremity is divided into four main regions:

Shoulder Region: Including the shoulder girdle (scapula and clavicle) and glenohumeral joint
Arm (Brachium): The region from shoulder to elbow, containing the humerus
Forearm (Antebrachium): The region from elbow to wrist, containing the radius and ulna
Hand (Manus): The wrist, palm, and fingers, containing carpals, metacarpals, and phalanges

Bones of the Upper Extremity

The skeletal framework of the upper extremity consists of 30 bones per limb, providing the structure necessary for muscle attachment and joint formation.

Shoulder Girdle

The shoulder girdle connects the upper extremity to the axial skeleton and consists of:

Clavicle (Collarbone): An S-shaped bone that articulates with the sternum medially and the scapula laterally, providing the only bony connection between the upper limb and the trunk
Scapula (Shoulder Blade): A flat, triangular bone that glides along the posterior thoracic wall, providing attachment for numerous muscles and forming part of the shoulder joint

Arm

Humerus: The longest and largest bone of the upper limb, extending from the shoulder to the elbow. Key features include:
- Head: Articulates with the scapula's glenoid cavity
- Greater and lesser tubercles: Attachment sites for rotator cuff muscles
- Deltoid tuberosity: Attachment site for the deltoid muscle
- Medial and lateral epicondyles: Attachment sites for forearm muscles

Forearm

Radius: The lateral bone of the forearm (thumb side), crucial for wrist and hand movements. It articulates with the humerus proximally and the carpal bones distally
Ulna: The medial bone of the forearm (pinky side), providing stability to the elbow joint. The olecranon process forms the bony prominence of the elbow

Hand

The hand contains 27 bones divided into three groups:

Carpals (8 bones): Arranged in two rows, these small bones form the wrist and provide flexibility while maintaining stability
- Proximal row: Scaphoid, lunate, triquetrum, pisiform
- Distal row: Trapezium, trapezoid, capitate, hamate
Metacarpals (5 bones): Form the palm of the hand, numbered 1-5 from thumb to pinky
Phalanges (14 bones): Form the fingers
- Thumb has 2 phalanges (proximal and distal)
- Each finger has 3 phalanges (proximal, middle, and distal)

For detailed information about bone structure and function, see our comprehensive lesson on The Bones of the Upper Limb: Structure, Function, and Clinical Relevance.

Muscles of the Upper Extremity

Over 50 muscles control movement and provide stability to the upper extremity. These muscles can be organized by region and function.

Shoulder Muscles

The shoulder is controlled by several muscle groups:

Rotator Cuff Muscles (SITS):

Supraspinatus: Initiates arm abduction
Infraspinatus: External rotation
Teres minor: External rotation and adduction
Subscapularis: Internal rotation

Larger Shoulder Movers:

Deltoid: Prime mover for arm abduction (anterior, middle, and posterior heads)
Latissimus dorsi: Powerful arm extensor and adductor ("pull-up muscle")
Pectoralis major: Arm flexion, adduction, and internal rotation
Teres major: Arm extension, adduction, and internal rotation

Arm Muscles

Anterior Compartment (Flexors):

Biceps brachii: Elbow flexion and forearm supination (two-headed muscle)
Brachialis: Primary elbow flexor, lies deep to biceps
Coracobrachialis: Arm flexion and adduction

Posterior Compartment (Extensors):

Triceps brachii: Primary elbow extensor (three-headed muscle, essential for push-ups and dips)

Forearm Muscles

The forearm contains approximately 20 muscles divided into:

Anterior (Flexor) Compartment:

Superficial layer: Flexor carpi radialis, palmaris longus, flexor carpi ulnaris
Intermediate layer: Flexor digitorum superficialis
Deep layer: Flexor digitorum profundus, flexor pollicis longus

Posterior (Extensor) Compartment:

Superficial layer: Extensor carpi radialis longus/brevis, extensor digitorum, extensor carpi ulnaris
Deep layer: Abductor pollicis longus, extensor pollicis longus/brevis, extensor indicis

Hand Muscles

Intrinsic hand muscles provide fine motor control:

Thenar muscles: Control thumb movements (abductor pollicis brevis, flexor pollicis brevis, opponens pollicis)
Hypothenar muscles: Control pinky finger movements
Lumbricals and interossei: Control finger flexion/extension and abduction/adduction

For an in-depth exploration of upper extremity musculature, see The Muscles of the Upper Extremity: Structure, Function, and Clinical Relevance.

Joints and Movement

The upper extremity contains multiple joint types, each contributing to its remarkable mobility.

Major Joints

Shoulder (Glenohumeral) Joint:

Type: Ball-and-socket synovial joint
Range of Motion: Flexion/extension, abduction/adduction, internal/external rotation, circumduction
Stability: Provided by rotator cuff muscles, labrum, and joint capsule
Clinical Note: Most mobile joint in the body, but also most prone to dislocation

Elbow Joint Complex:

Humeroulnar joint: Hinge joint allowing flexion/extension
Humeroradial joint: Pivot joint allowing pronation/supination
Range of Motion: ~145° flexion, ~180° pronation/supination

Wrist (Radiocarpal) Joint:

Type: Condyloid synovial joint
Range of Motion: Flexion/extension (85°/70°), radial/ulnar deviation (15°/30°)
Function: Allows hand positioning for optimal grip and manipulation

Hand Joints:

Carpometacarpal joints: Especially mobile in the thumb (saddle joint)
Metacarpophalangeal joints: Allow flexion/extension and abduction/adduction
Interphalangeal joints: Hinge joints allowing flexion/extension

Biomechanics of Common Movements

Understanding how joints work together is essential for calisthenics:

Push-up Movement:

Shoulder: Horizontal adduction (pectoralis major, anterior deltoid)
Elbow: Extension (triceps brachii)
Scapula: Protraction (serratus anterior)
Wrist: Extension (wrist extensors provide stability)

Pull-up Movement:

Shoulder: Extension and adduction (latissimus dorsi, teres major)
Elbow: Flexion (biceps brachii, brachialis)
Scapula: Depression and retraction (lower trapezius, rhomboids)
Forearm: Pronation or supination depending on grip

Handstand:

Shoulder: Maximal flexion (deltoids, especially anterior)
Elbow: Full extension (triceps maintain lockout)
Scapula: Upward rotation (trapezius, serratus anterior)
Wrist: Extension (wrist extensors crucial for balance)

Clinical Relevance for Calisthenics Athletes

Understanding upper extremity anatomy helps athletes prevent injuries and optimize performance.

Common Injuries

Shoulder Impingement:

Cause: Compression of rotator cuff tendons under the acromion
Prevention: Maintain balanced shoulder strength, proper scapular positioning
Relevant exercises: Face pulls, external rotation work

Elbow Tendonitis:

Medial epicondylitis: "Golfer's elbow" from excessive flexion/pronation
Lateral epicondylitis: "Tennis elbow" from excessive extension/supination
Prevention: Gradual progression, balanced training, proper form

Wrist Strains:

Cause: Excessive load in extended position (handstands, planches)
Prevention: Wrist mobility work, gradual conditioning, proper warm-up
Strengthening: Wrist curls, rice bucket exercises, controlled stretching

Rotator Cuff Tears:

Cause: Repetitive overhead activities, sudden force, poor mechanics
Prevention: Strengthen rotator cuff, avoid muscle imbalances
Warning signs: Pain during overhead movements, weakness, night pain

Training Considerations

Progressive Overload:

Upper extremity joints, especially wrists and elbows, need time to adapt to new stresses
Increase training volume by no more than 10% per week
Allow 48-72 hours recovery between intensive upper body sessions

Balanced Development:

Push-to-pull ratio: Maintain 1:1 or favor pulling slightly (1:1.5) to prevent shoulder imbalances
Include both vertical and horizontal pushing/pulling
Don't neglect rotator cuff and forearm strengthening

Mobility and Flexibility:

Shoulder: Maintain at least 90° overhead mobility
Wrist: Work on extension flexibility for handstands (90° minimum)
Elbow: Maintain full extension to prevent contractures

Technique Focus:

Shoulder positioning: Keep shoulders "packed" (slight retraction and depression)
Elbow alignment: Avoid hyperextension or valgus stress
Wrist stability: Maintain neutral wrist during most exercises
Scapular control: Master scapular protraction/retraction for push-ups and front lever progressions

Functional Applications

Skill-Specific Anatomy

Handstand:

Primary stabilizers: Deltoids (anterior), serratus anterior, trapezius (upper)
Secondary: Core muscles, wrist extensors
Key anatomy: Overhead shoulder flexibility, strong scapular stabilizers

Planche:

Primary movers: Anterior deltoids, pectoralis major/minor, serratus anterior
Secondary: Biceps (maintain slight bend), wrist extensors
Key anatomy: Exceptional anterior chain shoulder strength, conditioned wrists

Muscle-up:

Pull phase: Latissimus dorsi, biceps brachii, posterior deltoids
Transition: Explosive shoulder extension, triceps activation
Push phase: Triceps brachii, anterior deltoids
Key anatomy: Strong pulling muscles, explosive power, coordinated muscle sequencing

One-arm Pull-up:

Primary: Latissimus dorsi, biceps brachii (working side)
Stabilizers: Core rotational control, scapular stabilizers
Key anatomy: Unilateral strength, grip strength, anti-rotation core strength

Summary

The upper extremity is a complex anatomical region essential for calisthenics performance. By understanding:

Bones: 30 bones per limb providing structure and protection
Muscles: Over 50 muscles enabling movement and stability
Joints: Multiple joint types allowing incredible range of motion
Biomechanics: How structures work together during specific movements
Clinical considerations: Common injuries and prevention strategies

Athletes can train more intelligently, reduce injury risk, and achieve their performance goals. Whether you're working toward your first pull-up or mastering advanced skills like the planche, a solid understanding of upper extremity anatomy provides the foundation for success.

Ready to Apply Your Knowledge?

Now that you understand upper extremity anatomy, put this knowledge into practice with our comprehensive Calisthenics Instructor Certification Program. Learn how to apply anatomical principles to exercise programming, injury prevention, and skill progression.