upper limb osteology

upper limb osteology

1. Humerus

   • The humerus is a long bone of the upper limb, which extends from the shoulder to the elbow.
     • The proximal aspect of the humerus articulates with the genoid fossa of the scapula, forming the humerus articulates with the glenoid fossa of the scapula, forming the glenohumeral joint. Distally, at the elbow joint, the humerus articulates with the head of the radius and trochlear notch of the ulna
       • Proximal Landmarks
         • The proximal humerus is marked by a head, anatomical neck, surgical neck, greater and lesser tubercles and intertubercular sulcus
         • The upper end of the humerus consist of the head. This faces medially, upwards and backwards and is separated from the greater and lesser tubercles by the anatomical neck.
         • The greater tubercle is located laterally on the humerus and has anterior and posterior surfaces. It serves as an attachment site for three oof the rotator cuff muscles.
         • The lessertubercle: Is much smaller, and more medially located on the bone. It only has an anterior surface. It provides attachment for the last rotator cuff muscle.
         • Separating the two tubercles is a deep groove, known as the intertubercular sulcus. The tendon of the long head of the biceps brachiiemerges from the shoulder joint and runs through this groove.
         • The edges of the intertubercular sulcus are known as lips. Pectoralis major, teres major and latissimus dorsi insert on the intertubercular sulcus. This can be remembered with the mnemonic.
         • The surgical neck runs from just distal to the tubercles to the shaft of the humerus. The axillary never and circumflex vessels lie against the bone here.
         • Shaft
           • The shaft of the humerus is the site of attachment for various muscles. Cross section views reveal it to be circular proximally and flattened distally.
           • On the lateral side of the humeral shaft is a roughened surface where the deltoid muscle attaches. this is known is as the deltoid tuberosity.
           • The radial groove is a shallow depression that runs diagonally down the humerus, parallel to the deltoid tuberosity. The radial never and profunda brachii artery lie in this groove. The following muscles attach to the humerus along its shaft:
           • Anteriorly
           • Posteriorly
         • Distal Region
           • The lateral and medial borders of the distal humerus from medial and lateral supraepicondylar ridges. The lateral supraepicondylar ridge is more roughened, providing the site of common origin of the forearm estensor muscles.

2. Cavicle

   • The cavicle extends between the manubrium of the sternum and the acromionnof the scapula. It is classed as a long its lenght.
     • Function:
       • Attaches: The upper limb to the trunk as part of the shoulder girdle.
       • Protects: The underlying neurovascular structures supplying the upper limb.
       • Transmits force: From the upper limb to the axial skeleton.
     • Bony landmarks and articulations
       • The clavicle is a slender bone with an "S" shape. Facing forward, the medial aspect in convex, and the lateral aspect concave. It can be divided into a sternal end, a shaft and an acromial end.
         • Sternal end
           • The sternal end contains a large facet for articulation with the manubrium of the sternum at the sternoclavicular joint.
           • The inferior surface of the sternalend is marked by a rough oval depression for the costoclavicular ligament.
         • Shaft
           • The shaft of the clavicle acts a point of origin and attachment for several muscles: deltoid, trapezius, pectoralis major,sternocleidomastoid and sternohyoid.
         • Acromial end
           • The acromial end houses a small facet for articulation with the acromion of the scapula at the acromioclavicular joint. It also serves as an attachment point for two ligaments:
             • Conoid tubercle: Attachment point of the trapezoid ligament, the medial part of the coracoclavicular ligament.
             • Trapezoid line: Attachment point of the trapezoid ligament, the lateral part of the coracoclavicular ligament.

3. Scapula

   • The scapula is also known as the shoulder blade. it articulates with the humerus at the glenohumeral joint, and with the clavicle at the acromoclavicular jointg. in doing so, the scapula connects the upper limb to the trunk.
     • Costal Surface
       • The costal surface of the scapula faces the ribcage. It contains a large concave depression over most of its surface, know as the subscapular fossa. The subscapular surface of the costal scapula is the coracoid process. It is a hook-like projection, which lies just underneath the clavicle.
     • Lateral Surface
       • The lateral surface of the scpula faces the humerus. It is the site of the glenohumeral joint, and of various muscle attachments. it´s importan bony landmarks include:
         • Glenoid fossa
           • A shallow cavity, located superiorly on the lateral border. It articulates with the head of the humerus to form the glenohumeral joint.
         • Supraglenoid tubercle
           • A roughening immediately superior to the glenoid fossa. The place of the attachment of the biceps brachiiñ.
         • Infraglenoid tubercle
           • A roughening immediately inferior to the glenoid fossa. The place of attachment of the triceps brachii.
     • Posterior Surface
       • The posterior surface oh the scapula faces outwards. It is a site of origin for the majority of the rotator cuff muscles of the shoulder.
         • Spine
           • The most prominent feature of the posterior scapula. It runs transverserly across the scapula, dividing the surface into two.
         • Acromion
           • Projection of the spine that arches over the glenohumeral joint and articulates with the cavicle at the acromioclavicular joint.
         • Intraspinous fossa
           • The area below the spine of the scapula, it displays a convex shape. The infraspinatus muscle originates from this area.
         • Supraspinous fossa
           • The area above the spine of the scapula, it is much smaller than the infraspinious fossa, and is more convex in shape. The suprapinous muscle originates from this area.

4. Ulna

   • The unla is a long bone in the forearm. It lies medially and parallel to the radius, the second of torearm bones, The unla acts as the stabilsing bone, with the radius pivoting to produce movement.
     • Proxximally, the ulna articulates whit the humerus
       • Proximal Osteology and Articulation
         • The proximal end of the unla articulates with the trochlea of the humerus, To enable movement at the elbow joint, the unla has a specialised sutructure, with bony prominences for muscles attachment.
           • Olecranon
           • coronoid process
           • Trochlear notch
           • Tuberosity of ulna
   • Shaft
     • The ulnar shaft is triangular in shape, with three surfaces. As it moves distally, it decreases in width.
       • borders
         • posterior
         • interosseous
         • anterior
       • surface
         • anterior
         • posterior
         • medial

5. Radius

   • The radius is a long bone in the forearm. It lies laterally ans parallel to unla, the second of the forearm bones. The radius pivots around the unla to produce movement at the proximal and distal radio-ulnar joints.
     • Elbow join
     • Proximal radioulnar joint
     • wrist joint
     • Distal radioulnar joint
   • Proximal Region of the Radius
     • Head of radius
     • Neck of radius
     • Radial Tuberosity
   • Distal Region of Radius
     • In the distal region, the radial shaft expands to form a rectangular end. tha lateral side projects distally as the styloid process. In the medial surface, ther is a concavity, called the ulnar notch, with articulates with the head of unla, formig the distal radioulnar joint.

6. Carp

   • A set of eight irregulary shaped bones. These are located in the wrist area.
     • scaphoid
     • lunated
     • Triquetrum
     • pisiform

7. Metacarpal

   • The metacarpal bones articulate proximally with the carpals, and distally with the proximal phalanges. they are numberd, and each associated wirth a digit.
     • Thumb 1
     • index finger 2
     • middle finger 3
     • Ring finger 4
     • Little finger 5

8. Phalanges

   • The phalanges are the bones oh the fingers. The thumb has a proximal and dital phalanx, while the rest of the digist have proximal, middle and distal phalanges.