Upper Limb – Joints and Bones | Anatomy2Medicine
13 joints of the upper limb

Upper Limb – Joints and Bones

Bones of the shoulder girdle

    • Clavicle (Collarbone)
      • Is the first bone to begin ossification during fetal development
      • it is the last one to complete ossification, at 21 years of age.

 

  • Is the only long bone to be ossified intramembranously.
  • Scapula
  • Spine of the Scapula

 

        • Gives origin for the deltoid and an insertion for the trapezius.

 

  • Acromion

 

        • Provides an origin for the deltoid and an insertion for the trapezius

 

  • Coracoid Process

 

        • Provides the origin of the coracobrachialis and biceps brachii
        • Provides insertion of the pectoralis minor

 

  • attachment site for the coracoclavicular, coracohumeral, and coracoacromial ligaments and the costocoracoid membrane.
  • Scapular Notch

 

        • is bridged by the superior transverse scapular ligament
        • converted into a foramen that transmits the suprascapular nerve.

 

  • Glenoid Cavity

 

        • Is deepened by the glenoid labrum for the head of the humerus.

 

  • Supraglenoid Tubercle

 

        • Provide origin for the tendons of the long head of the biceps brachii

 

  • Infraglenoid Tubercle

 

      • Provide origin for the tendons of the triceps brachii muscle

Bones of the arm and forearm

    • Humerus

 

  • Head

 

        • Articulates with the scapula at the glenohumeral joint.

 

  • Anatomic Neck

 

        • provides an attachment for the fibrous joint capsule.

 

  • Greater Tubercle

 

        • provides attachments for the supraspinatus, infraspinatus, and teres minor muscles.

 

  • Lesser Tubercle

 

        • provides an insertion for the subscapularis muscle.

 

  • Intertubercular (Bicipital) Groove

 

        • lodges the tendon of the long head of the biceps brachii muscle
        • Provides insertions for the
          • pectoralis major on its lateral lip
          • teres major on its medial lip
          • latissimus dorsi on its floor.

 

  • Surgical Neck

 

        • Is a narrow area distal to the tubercles
        • a common site of fracture
        • it is in contact with the axillary nerve and the posterior humeral circumflex artery.

 

  • Deltoid Tuberosity

 

        • It marks the insertion of the deltoid muscle.

 

  • Spiral Groove

 

        • Contains the radial nerve

 

  • Separates the origin of the lateral head of the triceps above and the origin of the medial head below.
  • Trochlea

 

        • Is a spool-shaped medial articular surface
        • articulates with the trochlear notch of the ulna.

 

  • Capitulum

 

        • Is the lateral articular surface
        • globular in shape,
        • articulates with the head of the radius.

 

  • Olecranon Fossa

 

        • Is a posterior depression above the trochlea of the humerus
        • houses the olecranon of the ulna on full extension of the forearm.

 

  • Coronoid Fossa

 

        • Is an anterior depression above the trochlea of the humerus
        • accommodates the coronoid process of the ulna on flexion of the elbow.

 

  • Radial Fossa

 

        • Is an anterior depression above the capitulum
        • occupied by the head of the radius during full flexion of the elbow joint.

 

  • Lateral Epicondyle

 

        • provides the origin of the supinator and extensor muscles of the forearm.

 

  • Medial Epicondyle
  • Projects has a groove on the back for the ulnar nerve and superior ulnar collateral artery.

 

        • Provides attachment sites for the

 

  • ulnar collateral ligament
  • pronator teres
  • common tendon of the forearm flexor muscles.

 

    • Radius
      • Is shorter than the ulna
      • situated lateral to the ulna.
      • fractured at its distal end (Colles’s fracture).
      • Is characterized by displacement of the hand dorsally and radially

 

  • Head (Proximal End)

 

        • Articulates with the capitulum of the humerus and the radial notch of the ulna
        • is surrounded by the annular ligament.

 

  • Distal End
  • Articulates with the proximal row of carpal bones, including the scaphoid, lunate, and triquetral bones but excluding the pisiform bone.
  • Radial Tuberosity

 

        • provides an attachment site for the biceps brachii tendon.

 

  • Styloid Process

 

        • is approximately 1 cm distal to that of the ulna
        • provides insertion of the brachioradialis muscle.

 

  • Can be palpated in the proximal part of the anatomic snuffbox between the extensor pollicis longus and brevis tendons.

 

  • Ulna
    • Olecranon
      • provides an attachment site for the triceps tendon
    • Coronoid Process
      • provides an attachment site for the brachialis.
    • Trochlear Notch
      • Receives the trochlea of the humerus
    • Ulnar Tuberosity
      • provides an attachment site for the brachialis.
    • Radial Notch
      • Accommodates the head of the radius at the proximal radioulnar joint.
    • Head (Distal End)
      • Articulates with the articular disk of the distal radioulnar joint and has a styloid process.

Bones the hand

    • Carpal Bones

 

  • Are arranged in two rows of four (lateral to medial)

 

      • scaphoid, lunate, triquetrum, pisiform
      • trapezium, trapezoid, capitate, and hamate

 

  • Proximal Row (Lateral to Medial): Scaphoid, Lunate, Triquetrum, and Pisiform

 

      • Except for the pisiform, articulates with the radius and the articular disk (the ulna has no contact with the carpal bones).

 

  • The pisiform is said to be a sesamoid bone contained in the flexor carpi ulnaris tendon.(MCQ)
  • Distal Row (Lateral to Medial)
  • Trapezium, Trapezoid, Capitate, and Hamate

 

 

    • Fracture of the clavicle
      • results from
        • a fall on the shoulder or outstretched hand
        • caused by the obstetrician in breech presentation
        • when the infant presses against the maternal pubic symphysis during its passage through the birth canal.
      • Its fracture in the middle third (the most common fracture site)
      • results in
        • upward displacement of the proximal fragment by the sternocleidomastoid muscle
        • downward displacement of the distal fragment by the deltoid muscle and gravity.
      • It may cause injury to the brachial plexus (lower trunk),
      • causes paresthesia (sensation of tingling, burning, and numbness) in the area of the skin supplied by medial brachial and antebrachial cutaneous nerves
      • cause fatal hemorrhage from the subclavian vein
      • responsible for thrombosis of the subclavian vein, leading to pulmonary embolism.
    • Calcification of the superior transverse scapular ligament
      • may trap or compress the suprascapular nerve as it passes through the scapular notch under the superior transverse scapular ligament
      • affects functions of the supraspinatus and infraspinatus muscles.
    • Fracture of the greater tuberosity
      • occurs by

 

  • direct trauma

 

        • by violent contractions of the supraspinatus muscle.
      • The bone fragment has the attachments of the supraspinatus, infraspinatus, and teres minor muscles, whose tendons form parts of the rotator cuff.
    • Fracture of the lesser tuberosity
      • accompanies posterior dislocation of the shoulder joint
      • bone fragment has the insertion of the subscapularis tendon.

 

  • Fracture of the surgical neck

 

      • may injure the axillary nerve and the posterior humeral circumflex artery as they pass through the quadrangular space.
    • Colles’s fracture of the wrist
      • is a distal radius fracture
      • distal fragment is displaced (tilted) posteriorly
      • produces a characteristic bump described as dinner (silver) fork deformity
      • If the distal fragment is displaced anteriorly, it is called a reverse Colles’s fracture (Smith’s fracture).
    • Fracture of the scaphoid

 

  • occurs after a fall on the outstretched hand
  • shows a deep tenderness in anatomical snuffbox

 

      • damages the radial artery
      • cause avascular necrosis of the bone and degenerative joint disease of the wrist.
    • Fracture of the hamate

 

  • may injure the ulnar nerve and artery because they are near the hook of the hamate.

 

    • Bennett’s fracture
      • a fracture of the base of the metacarpal of the thumb
    • Boxer’s fracture
      • a fracture of the necks of the second and third metacarpals, seen in professional boxers
      • typically of the fifth metacarpal in unskilled boxers.

 

  • which causes pain, numbness, and tingling in the ring and little fingers
  • Guyon’s canal (ulnar tunnel)

 

    • formed by the pisiform, hook of the hamate, and pisohamate ligament
    • exists deep to the palmaris brevis and palmar carpal ligament

 

  • transmits the ulnar nerve and artery.
  • Guyon’s canal syndrome

 

    • entrapment of the ulnar nerve in the Guyon’s canal,

Joints and ligaments of the upper limb

    • Acromioclavicular Joint
      • Is a synovial plane joint
      • allows a gliding movement when the scapula rotates

 

  • reinforced by the coracoclavicular ligament, which consists of the conoid and trapezoid ligaments.

 

    • Sternoclavicular Joint
      • Is a double synovial plane (gliding) joint (MCQ)
      • united by the fibrous capsule.

 

  • Is reinforced by the anterior and posterior sternoclavicular, interclavicular, and costoclavicular ligaments.
  • Allows elevation and depression, protraction and retraction, and circumduction of the shoulder.

 

    • Shoulder (Glenohumeral) Joint
      • Is a synovial ball-and-socket joint
      • Both articular surfaces are covered with hyaline cartilage.
      • Is surrounded by the fibrous capsule that is attached
        • superiorly to the margin of the glenoid cavity

 

  • inferiorly to the anatomic neck of the humerus
  • The capsule is reinforced by the rotator cuff, the glenohumeral ligaments, and the coracohumeral ligaments.

 

      • Has a cavity that is deepened by the fibrocartilaginous glenoid labrum
      • communicates with the subscapular bursa
      • May be subject to inferior or anterior dislocation
        • may injure the axillary nerve.

 

  • Rotator (Musculotendinous) Cuff
  • Is formed by the tendons of the supraspinatus, infraspinatus, teres minor, and subscapularis (SITS)

 

        • fuses with the joint capsule
        • Keeps the head of the humerus in the glenoid fossa during movements and thus stabilizes the shoulder joint.

 

  • Ligaments of the shoulder joint
  • Glenohumeral Ligaments

 

          • superior glenohumeral ligament)
          • middle glenohumeral ligament
          • inferior glenohumeral ligament

 

  • Transverse Humeral Ligament
  • Coracohumeral Ligament
  • Coracoacromial Ligament

 

        • Coracoclavicular Ligament
    • Bursae Around the Shoulder

 

  • Subacromial Bursa

 

        • protects the supraspinatus tendon against friction with the acromion.

 

  • Subdeltoid Bursa

 

        • Lies between the deltoid muscle and the shoulder joint capsule
        • usually communicates with the subacromial bursa
        • facilitates the movement of the deltoid muscle over the joint capsule and the supraspinatus tendon.

 

  • Subscapular Bursa

 

        • Lies between the subscapularis tendon and the neck of the scapula
        • communicates with the synovial cavity of the shoulder joint.
    • Elbow Joint
      • Forms a synovial hinge joint (MCQ)
      • Consist of the humeroradial and humeroulnar joints
      • allows flexion and extension

 

  • It also includes the proximal radioulnar (pivot) joint, within a common articular capsule.

 

      • Is reinforced by the following ligaments:

 

  • Annular Ligament

 

          • Is a fibrous band that forms nearly four-fifths of a circle around the head of the radius; the radial notch forms the remainder.
          • Encircles the head of the radius

 

  • holds it in position and fuses with the radial collateral ligament and the articular capsule.
  • Lifting a child by the child’s forearm may dislocate head of the radius from the annular ligament. (MCQ)
  • Radial Collateral Ligament
  • Ulnar Collateral Ligament

 

    • Proximal Radioulnar Joint
      • Forms a synovial pivot joint
      • head of the radius articulates with the radial notch of the ulna
      • allows pronation and supination
      • permit the head of radius to rotate within the encircling annular ligament.
    • Distal Radioulnar Joint
      • Forms a synovial pivot joint
      • Forms between the head of the ulna and the ulnar notch of the radius
      • allows pronation and supination.
    • Wrist (Radiocarpal) Joint
      • Is a synovial condylar joint
      • formed superiorly by the radius and the articular disk
      • formed inferiorly by the proximal row of carpal bones (scaphoid, lunate, and rarely triquetrum).
      • Its capsule is strengthened by radial and ulnar collateral ligaments and dorsal and palmar radiocarpal ligaments
      • it allows flexion and extension, abduction and adduction, and circumduction.
    • Midcarpal Joint
      • Forms a synovial plane joint
      • between the proximal and distal rows of carpal bones
      • allows gliding and sliding movements.
    • Carpo metacarpal Joints

 

  • Form synovial saddle (sellar) joints

 

      • between the carpal bone (trapezium) and the first metacarpal bone
      • plane joints between the carpal bones and the medial four metacarpal bones
      • allows a simple gliding movement.
    • Meta carpo phalangeal Joints
      • Are condyloid joints
    • Interphalangeal Joints
      • Are hinge joints that allow flexion and extension.
    • Dislocation of the acromioclavicular joint
      • results from a fall on the shoulder with impact taken by the acromion
      • results from from a fall on the outstretched arm.
      • Why is it  called a shoulder separation
        • shoulder is separated from the clavicle when the joint dislocation causes  rupture of the coracoclavicular ligament
      • occurs usually in the anteroinferior direction because of the lack of support by tendons of the rotator cuff
      • It may damage the axillary nerve and the posterior humeral circumflex vessels.

 

  • Referred pain to the shoulder

 

      • most probably indicates involvement of the phrenic nerve (or diaphragm).

 

  • The supraclavicular nerve (C3–C4), which supplies sensory fibers over the shoulder, has the same origin as the phrenic nerve (C3–C5), which supplies the diaphragm.
  • Rupture of rotator cuff

 

    • occur by
      • a chronic wear and tear most frequently with attrition of the supraspinatus tendon by friction among middle-aged persons
      • an acute fall on the outstretched arm
    • manifested by severe limitation of shoulder joint motion, chiefly abduction
    • may cause degenerative inflammatory changes (degenerative tendonitis) of the rotator cuff
    • results in a painful abduction of the arm or a painful shoulder.