0:00 The hip joint is a strong and stable ball and socket type of synovial joint, 0:16 which forms 0:16 the connection between the lower limb and the pelvic girdle. 0:20 The head of the femur is the ball and the acetabulum is the socket. 0:25 Compared for the depression or the fovea for the ligament of the femoral head, 0:30 all of the 0:30 femoral head is covered with articular cartilage, which is usually thickest 0:35 over weight bearing 0:36 areas. 0:42 The hip joint is a multi-axial joint, meaning it has a wide range of motion. 0:47 We can do flexion, extension, abduction, adduction, external rotation, internal 0:59 rotation, and 1:00 circumduction. 1:08 Let's talk about the joint capsule of the hip. 1:12 The hip joints are enclosed within a strong joint capsule. 1:18 The capsule is formed by the external fibrous layer, known as the fibrous 1:25 capsule, which 1:27 also forms part of the ligaments of the hip, and then the internal synovial 1:34 membrane, 1:36 which is a membrane that contains a synovial fluid. 1:41 Let's focus on the fibrous capsule. 1:44 Now, proximally, the fibrous layer attaches to the acetabulum. 1:51 Distantly, the fibrous layer attaches to the femoral neck, only anteriorly at 1:57 the intertrochanteric 1:59 line in the root of the greater trochanter, and then posteriorly, the fibrous 2:03 layer crosses 2:04 the femoral neck proximal to the intertrochanteric crest, but does not actually 2:09 attach to it. 2:11 The thick parts of the fibrous layer help form the ligaments of the hip joint. 2:23 So, the ligaments of the hip joint, briefly, just acts to increase the 2:30 stability of the 2:32 hip joint. 2:33 They can be divided into two groups, intracapsular ligaments and extracapsular 2:41 ligaments. 2:43 The intracapsular ligaments, well, there's only one, and this is the ligament 2:48 of the 2:48 head of the femur, which runs from the acetabular fossa to the folvia of the 2:55 femur. 2:56 It actually encloses a branch of the obturator artery, known as the folvial 3:02 artery, a minus 3:03 source of arterial supply to the hip joint, and this is mainly during pediatric 3:15 age. 3:16 The extracapsular ligaments are more important in adulthood, and the names of 3:24 the extracapsular 3:26 ligaments are based on where the ligament attaches to the pelvis, and the pel 3:31 vis is 3:31 made up of the, briefly, ileum, ischium, and pubis. 3:38 So first you have the ileophamoral ligament, which is the strongest of the 3:42 three ligaments, 3:43 and then you have the pubofamoral ligament, and the ischio-famoral ligament. 3:49 Again, the extracapsular ligament passes in a spiral fashion from the pelvis to 3:56 the femur, 3:58 and this causes them to become tighter. 4:03 Flexion of the hip joint increasingly unwinds the spiraling ligaments and 4:07 fibers, and this 4:08 allows for more mobility of the hip joint inflection. 4:13 Let's look at some clinical anatomy, firstly, the dislocation of the hip joint. 4:22 Now, dislocation of the hip joint can occur as a congenital dislocation, and 4:27 here the 4:28 hip joint is one of the most common joints affected. 4:31 It occurs due to two main reasons. 4:33 Firstly, the joint capsule is loose at birth, or you can have hypoplasia of the 4:39 acetabulum 4:40 and femoral head. 4:45 And here you can see images of testing in a baby for hip dislocation. 4:54 Then you have a quiet hip dislocation, and in a quiet dislocation, it is 5:01 uncommon because 5:03 as mentioned, the hip joint is usually very stable. 5:06 A posterior dislocation of the hip joint is most common and can occur in car 5:11 accidents. 5:12 This is because when driving, your hip is flexed, so the ligaments are relaxed, 5:16 remember. 5:17 And the joint is unstable. 5:19 Head on collision forces the femur out of the acetabulum, causing a shortened 5:24 and internally 5:25 rotated limb. 5:31 Let's talk about the blood supply. 5:33 The blood supply to the hip joint is from the medial and lateral femoral circum 5:37 flex arteries, 5:38 which form the extracapsular ring and give rise to the cervical arteries. 5:43 I'll have a video that talks more about neck or femur fractures, which goes 5:47 into this 5:48 in detail. 5:50 Another direct source of blood supply to the fema is from the foveal artery, 5:54 which only 5:54 occurs in the pediatric population. 5:57 Because eventually this is replaced by the ligamentum terrace. 6:00 The ligamentum terrace is the ligament connecting the head of the femur to the 6:09 acetabulum. 6:11 Another blood supply is from the cruciate anastomosis, which is between the 6:15 inferior 6:16 gluteal artery and the medial circumflex femoral artery. 6:25 Some clinical anatomy, a vasculonic crisis of the femoral head, or osteonic 6:30 crisis of 6:31 the femoral head, is characterized as bone cell death that occurs following an 6:36 impairment 6:37 of blood flow to the bone from a traumatic or a non-traumatic origin. 6:44 As we have learned, the blood supplying the femoral head rely on small arteries 6:49 with limited 6:50 collateral blood supply, and so the femoral head is a very easy spot where you 6:56 can have 6:57 lack of blood supply, causing necrosis. 7:06 Another clinical anatomy to know is what's known as perthys disease. 7:11 Perthys disease is an idiopathic avascular necrosis of the capital femoral epip 7:18 hesies. 7:19 And this is usually affecting children, again between ages 4 and 12 years old. 7:29 It more commonly affects male, and also children exposed to maternal smoking 7:35 during pregnancy. 7:37 Clinically, when you have perthys disease, this causes destruction and flatt 7:41 ening of 7:42 the head of the femur with an increased joint space on X-ray as you can see. 7:52 The hip joint is innervated primarily by the sciatic femoral and obturator 7:57 nerves. 7:58 These same nerves innervate the knee as well, which explains why pain can be 8:03 referred to 8:03 the knee from the hip joint and vice versa. 8:12 Now let's talk about the muscles that acts on the hip joint. 8:18 We already learned about the motions of the hip joint. 8:21 Now let's talk about the muscles. 8:22 So the main flexes of the hip joint are the ileosos muscles, which include the 8:28 psoas major 8:29 and iliacus, as well as a rectus femoris muscle. 8:33 To a lesser extent, you have other flexes, including sartorius and pectinius. 8:41 The primary extensors of the hip joint is the gluteus maximus muscle, assisted 8:48 by the hamstring 8:49 muscles, biceps femoris, semitoneosis and semimembranosis, as well as the ad 8:55 ductor 8:55 magnus muscle. 9:04 The primary AB ductors of the hip joint are the gluteus medius and gluteus 9:08 minimus muscles. 9:11 The major adductors of the hip joint are the adductors longus, adductors brevis 9:19 and magnus, 9:21 as well as the gracillus muscle. 9:31 Internal rotators of the hip joint include the anterior fibers of the gluteus 9:35 medius 9:36 and minimus, external rotators is produced by the gluteus maximus, together 9:41 with a group 9:42 of six small muscles, which include the piriformis, obturator internus, 9:48 superior and inferior 9:50 gemuli and quadratus femoris and obturator externus. 10:01 Now that we've learned about the muscles and what they do at the hip joint, we 10:06 can now 10:07 understand some of the examination techniques for the hip joint, beginning with 10:12 the Trendelenburg 10:14 test. 10:15 The Trendelenburg sign is a physical examination finding seen when assessing 10:20 for someone with 10:21 a dysfunctional hip. 10:23 Patients are asked to stand on one leg, and the position of the pelvis is noted 10:29 . 10:30 So if the pelvis drops, so for example on the left hand side here the pelvis is 10:37 dropped, 10:38 the patient may sway to the loaded leg and the test is positive. 10:46 Now a positive Trendelenburg sign will indicate weakness in the hip AB ducted 10:53 muscles, of 10:54 which is the gluteus medius and minimus, on the side that the leg is standing 11:05 on. 11:06 Another test is known as Thompson's test. 11:09 This test helps unmask a fixed flexion deformity of the hip, and measure the 11:15 true range of hip 11:17 flexion, with the patient supine fully flex one hip, make sure the lower back 11:26 is flat. 11:27 If the contralateral hip lifts off the table, there is a likely fixed flexion 11:35 deformity of 11:36 that leg, and it could be due to tightness, for example, of the ileososus 11:42 muscle or the 11:43 rectus femoris muscle, which are the muscles involved in hip flexion. 11:54 So in summary, the hip joint is a strong and stable ball and socket type of syn 11:59 ovial joint, 12:00 which forms a connection between the lower limb and the pelvic girdle. 12:04 The hip joint is a multi-axial joint, meaning it has a wide range of movement, 12:09 flexion 12:09 extension, abduction, adduction, external and internal rotation. 12:15 The hip joints are enclosed within a strong joint capsule, which is formed by 12:19 the external 12:20 fibrous layer and the internal synovial membrane. 12:25 Thank you for watching. 12:39 You
