The Sternoclavicular Joint (Bau-P1-2023)

THE STERN O CLAVICU LAR JOINT  The sternoclavicular joint is a saddle type synovial joint (sometimes called a double-plane joint) between the clavicle and the manubrium of the sternum. It is the only attachment of the upper limb to the axial skeleton. Despite its strength, i...

THE STERN O CLAVICU LAR JOINT  The sternoclavicular joint is a saddle type synovial joint (sometimes called a double-plane joint) between the clavicle and the manubrium of the sternum. It is the only attachment of the upper limb to the axial skeleton. Despite its strength, it is a very mobile joint and canfunction, more like a ball-and-socket type joint but it is not actually.  Bilateral joint can be palpated Joint is in between chest and Collar bone Also include first rib so that what movement it does then ribs also affecting Double plane joint Joint Structure - Articulating Surfaces The sternoclavicular joint consistsof the sternal end of the clavicle, the manubrium of the sternum, and part of the 1st costalcartilage. The articular surfaces are covered with fibrocartilage (as opposed to hyaline cartilage, present in the majority of synovial joints). Even hyaline is the book- coverer of the body. The joint is separated into two Cartilage Types; compartments by a -Hyaline Cartilage fibrocartilaginous articular disc. -Elastic Cartilage -Fibrous Cartilage Very interesting, one of the unique in that size of joint we have an ‘’articular disk’’. The joint is having the disk inside that separates the capsule in two compartments and this is pretty much similar to the joint that we are going to see at the head, ‘’tempora-mandibular joint’’. Fibrocartilage White fibrocartilage consists of a mixture of white fibrous tissue and cartilaginous tissue in various proportions. It owes its flexibility and toughness to the former of these constituents, and its elasticity to the latter. It is the only type of cartilage that contains type I collagen in addition to the normal type II. *Flexibility *Elasticity There are some specific joint that are covered with fibrous type of cartilage ; -Temporamandibular joint -Sternoclavicular disk -Anulus fibrosus (intervertabral disks) -Pubic symphysis -Menisci -Triangular fibrocartilage *Very specific cartilage tissue *Distal part of the ulna and at the wrist Details; -Anulus:Ring: fibrosus (intervertabral disks) *Covering the disk *Bodies’ are covered with hyaline cartilage *Cheesy one is fibrocartilage -Vertebral discs are absorbing the shock Fibrocartilage Fibrocartilage is found in the pubic symphysis, the anulus fibrosus of intervertebral discs, menisci, the sternoclavicular disc, the triangular fibrocartilage and the TMJ (temporamandibularjoint). It is also present at the tendon bone interface, where there is a transition from soft tendon to un- calcified then calcified fibrocartilage before becoming bone. SOFT – UNCALCIFIED – CALCIFIED  During labor, relaxing loosens the pubic symphysis to aid in delivery, but this can lead to later joint problems. Type of cartilages is including disks and surfaces can be affected by the circulating hormones. For terms of relaxing and strengthing. Joint Structure - Joint Capsule Thejoint capsule consists of a fibrous outer layer, and inner synovial membrane. The fibrous layer extends from the epiphysis of the sternal end of the clavicle, to the borders ofthe articular surfacesand the articular disc. Outer: FIBROUS Inner: CONNECIVE TISSUE  A synovial membrane lines the inner surface and produces synovial fluid to reduce friction between the articulating structures. Articular surfaces are covered by fibrous cartilage Secreter of synovial fluid; Synovial membrane Joint Structure -Ligaments The ligaments of the sternoclavicular joint provide much of its stability. There are four major ligaments: Sternoclavicular ligaments (anterior and posterior) –these strengthen the joint capsule anteriorly and posteriorly. Interclavicular ligament – this spans the gap between the sternal ends of each clavicle and reinforces: pekiştirmek: the joint capsule superiorly. Costoclavicular ligament – the two parts of this ligament (often separated by a bursa) bind at the 1st rib and cartilage inferiorly Fixation and to the anterior and posterior borders 1st rib’s capsule attachment of the clavicle superiorly.  It is a very strong ligamentand is the main stabilising force for the joint, resisting elevation of the pectoralgirdle. Costoclavicular The sternoclavicular and interclavicular ligaments can be considered to be thickenings of the joint capsule. When we talk about ligament; -Thickening ligament (common) -True ligament (rare) As example of thickening ligaments; *Sternoclavicular ligament *Interclavicular ligament NeurovascularSupply Arterial supply to the sternoclavicular joint is from 2 arteries: *the suprascapular artery -branch of tyrocervical trunk *the internal thoracic artery -mammarian artery -branch of subclavian artery The joint is supplied by 2 nerves: *the medial supraclavicular nerve (C3 andC4) *the subclavius nerve -innervating subclavius muscle 31 pair of spinal nerve, we have. (C5 and C6) Suprascapular 3 sets of SUPRACLAVICULAR NERVES Movements Thesternoclavicular joint hasa large degree of mobility. There are several movements that require joint involvement: Elevation of the shoulders – shrugging the shoulders abducting the arm over 90º Depression of the shoulders – drooping shoulders extending the armat the shoulder behind the body Protraction of the shoulders –moving the shoulder girdleanteriorly Retraction of the shoulders – moving the shouldergirdleposteriorly Rotation – when the arm is raised:collecting: over the head by flexion theclavicle rotates passively asthe scapula rotates. This is transmitted to the clavicle by the coracoclavicularligaments Movements Movements The costoclavicular ligament acts asa pivot for movements of the clavicle. You can feel this if you palpate the sternal end of your clavicle and shrug your shoulders, you should feel the sternal end moving inferiorly.  Mobility andStability Thesternoclavicular joint is required to accommodate the movements of the upper limb, and thus has a high degree of mobility. However, it also requires much stability, as it is the only connectionbetween the upper limb and the axial skeleton. What makes a joint mobile or stable? Mobility Saddletypeof joint – being a saddlejoint it canmove in two axes. Articular disc – this allows the clavicle and the manubrium to slide over Saddle joint always eachother more freely, allowing for the moves in 2 axises rotation and movement in athird axis. Stability Strong joint capsule. Strong ligaments – particularly the costoclavicular ligament, which transfers stress from the clavicle to the manubrium (via the costalcartilage). Clinical Relevance:Dislocation of the Sternoclavicular Joint A dislocation of the sternoclavicular joint is quiterare and requires significantforce. The costoclavicular ligament and the articular disc are highly effective at absorbing and transmitting forces away from the joint into the sternum. Shock absorbers; *Costaclavicular ligament *Articular disk There are two major types of dislocation: Anterior dislocations are the mostcommon and can happen following a blow to the anterior shoulder which rotates theshoulder backwards. Posterior dislocations normally result from a force driving the shoulder forwards or from direct impact to thejoint. In younger people, the epiphysealgrowth plate of the sternal end of the clavicle hasnot fully closed. In this population, the dislocation is usually accompanied by a fracture through the plate (epiphysial). At young age: dislocation + fructure