Os coxae
The pelvis (os coxae) is formed by the fusion of three bones on each side: the ilium (cranially), the ischium (caudally), and the pubis (ventrally). These fuse at the acetabulum, which forms the socket of the hip joint. The two sides are joined ventrally at the pelvic symphysis and articulate dorsally with the sacrum at the sacroiliac joints. The ilium is the largest component and bears the tuber coxae (point of the hip) and tuber sacrale as important palpable landmarks. The ischial tuberosities (pin bones) are prominent caudally. The pelvis anchors the most powerful muscles in the body and transmits propulsive force from the hindlimbs through the sacroiliac joints to the spine. It also protects the pelvic organs.
Origin: N/A (bone)
Insertion: N/A (bone)
Action: Anchors hindquarter muscles; forms the hip joint; transmits propulsive force from the femur through the SI joint to the spine; protects pelvic organs
Pelvic fractures, sacroiliac strain or injury, and hip dysplasia or luxation can cause significant hindlimb lameness. The tuber coxae and ischial tuberosities are common landmarks and sites of traumatic injury. Pelvic asymmetry or pain on rectal examination warrants further investigation.
## Overview Pelvic fractures result from slipping, falling, or impact, or from stress in racehorses. Common sites include the tuber coxae (point of hip), ilial wing, and pelvic floor. Signs are acute
## Overview Pelvic stress fractures are incomplete cracks from repetitive loading, seen mainly in racehorses and most often involving the ilium or pubis. They cause hind-limb lameness that worsens wi
Hindlimb lameness that is worse on one side, asymmetry of the hips or croup, or reluctance to engage the hindquarters should be evaluated. Trauma to the point of the hip or pin bones needs veterinary assessment.
## Overview Pelvic fractures result from slipping, falling, or impact, or from stress in racehorses. Common sites include the tuber coxae (point of hip), ilial wing, and pelvic floor. Signs are acute severe hind-limb lameness, possible asymmetry of the pelvis, crepitus, and muscle atrophy. Diagnosis is by rectal palpation, ultrasound, or scintigraphy. ## Causes Trauma or fatigue failure. ## Diagnosis Rectal examination, ultrasound, and bone scan. Radiographs are difficult in adults. ## Treatment Strict stall rest for most fractures. Surgery is rarely feasible. Prognosis depends on the location and degree of displacement. Tuber coxae fractures often do well; more central fractures are more serious. ## Recovery and Prognosis Variable. Many tuber coxae and some ilial fractures heal with rest. Displaced acetabular or highly unstable fractures have a poor outlook. ## Prevention Safe footing and monitoring of racehorses for early stress changes. Signs include: acute severe hind-limb lameness; asymmetric pelvis; crepitus; muscle atrophy; confirmed on rectal palpation or ultrasound
## Overview Pelvic stress fractures are incomplete cracks from repetitive loading, seen mainly in racehorses and most often involving the ilium or pubis. They cause hind-limb lameness that worsens with exercise and may present only as poor performance. Nuclear scintigraphy is the gold-standard diagnostic tool. Rest resolves most cases if complete fracture is avoided. ## Causes Cyclical fatigue of bone. ## Diagnosis Bone scan. Ultrasound may detect more advanced cracks. ## Treatment Strict stall rest, often 60 days or longer. Hand-walking is usually avoided because muscle pull can propagate the fracture. ## Recovery and Prognosis Good if rested before complete fracture. Propagation to a complete fracture worsens the outlook dramatically. ## Prevention Careful monitoring of racehorses and modification of training when early soreness appears. Signs include: hind-limb lameness that worsens with exercise; poor performance; no obvious trauma; diagnosed on bone scan
Pelvic fractures, sacroiliac strain or injury, and hip dysplasia or luxation can cause significant hindlimb lameness. The tuber coxae and ischial tuberosities are common landmarks and sites of traumatic injury. Pelvic asymmetry or pain on rectal examination warrants further investigation.
Hindlimb lameness that is worse on one side, asymmetry of the hips or croup, or reluctance to engage the hindquarters should be evaluated. Trauma to the point of the hip or pin bones needs veterinary assessment.
See the Pelvis on our interactive 3D horse model. Open 3D Model