Superior Longitudinal Muscle of Tongue

The superior longitudinal muscle of tongue is one of the four intrinsic muscles which form this muscular organ of the oral cavity. It underlies the superficial mucous membrane and submucous fibrous layer of the tongue. It is made up of a thin layer of oblique and longitudinal muscular fibers. It is also known as superior lingualis in older text books.

Origin and Insertion

The superior longitudinal muscle of tongue arises from the lesser horns of the hyoid bone, by two lateral slips, and from the anterior surface of epiglottis by a medial slip. Then these three slips converge and pass immediately under the mucous membrane, running along the whole dorsum of the tongue to its tip, interlacing with one another.

The oblique muscular fibers, which constitute the superior longitudinal muscle, runs forward obliquely and laterally to the edges of the tongue. Meanwhile, its longitudinal fibers runs straight forwards to the tip of tongue. Both types of fibers insert themselves in between the extrinsic muscular fiber ends of the styloglossus, palatoglossus, hyoglossus, and chondroglossus muscles, which constitute the base of the tongue.

Innervation and Blood Supply

The superior longitudinal muscle of tongue is innervated by the hypoglossal nerve (CN XII) and is supplied by a branch of the lingual artery.

Action

This longitudinal lingual muscle raises the tip of tongue, curls it backwards, and shorten it, making it thicker. Thus, it is important when it comes to speech, because we use it when we pronounce some consonant letters.

Down below, the human tongue, showing the superior longitudinal muscle (superior lingualis). The surface of tongue (superficial mucous membrane and the submucous fibrous) layer have been removed to expose it.

Extrinsic Muscles of Tongue

The extrinsic muscles of tongue make up the muscular base of this organ. Some anatomists also refer to them as the skeletal muscles of tongue, since they are attached to bone. They are four muscles as two of them take part in deglutition (process of swallowing food). They are innervated by the hypoglossal nerve (CN XII) and supplied by the deep lingual and sublingual arteries, which are branches of the lingual artery.

1) Styloglossus muscle– It originates from the styloid process of temporal bone and the stylohyoid ligament, traveling obliquely downwards and forwards, joining the lateral aspect of the root of tongue. Function: it pulls the tongue backwards and upwards.

2) Hyoglossus muscle– It is square in shape, rising from the superior border of the body and the greater horn of the hyoid bone, with its fibers running upwards to insert to the side of the tongue, between the styloglossus and inferior longitudinal muscle. Action: it pulls the tongue backwards and downwards.

3) Genioglossus muscle– Lying on both sides of septum of tongue, it arises from spina mentalis of mandible and then runs up as it fans out to insert into the lingual fascia and the mucous membrane of tongue. Its posterior fibers insert into the body of the hyoid bone. It pulls the tongue forwards and downwards.

4) Chondroglossus muscle– It originates from the lesser horn of the hyoid bone and runs upwards, together and confused with the hyoglossus fibers. It is inserted into the dorsum of tongue.

Below, schematic picture of extrinsic muscles of human tongue. The chondroglossus cannot be seen because it runs between the muscular fibers of the hyoglossus muscle.

Chondroglossus Muscle

The chondroglossus muscle is one of the four extrinsic muscles of human tongue. It arises from the lesser horn of the hyoid bone by a small muscular slip. Then its fibers travel up obliquely and anteriorly between the muscular fibers of the hyoglossus as they get mixed up. It is inserted into the dorsum of the tongue, interlacing with the fibers of the superior longitudinal muscle of tongue.

Action

The chondroglossus pulls the tongue downwards and backwards, working together with the hyoglossus.

Innervation and Blood Supply

It is innervated by the hypoglossus nerve (CN XII) and it receives oxygenated blood from small collateral branches of the lingual artery.

Below, right side of human face, exhibiting the extrinsic muscle of tongue. To expose the chondroglossus, the hyoglossus has been cut off.

Genioglossus Muscle

The genioglossus muscle is located at the base of the tongue on both side of its septum. Triangular in shape, it is one of the extrinsic muscles of this organ. It originates from the mental spine of the mandible (called symphysis), fanning out as it extends backwards to insert into the lingual fascia and the hyoid bone.

Action

The genioglossus protrudes (sticks out) and depresses the tongue, pulling it forwards and backwards. Not only does it contribute in the motor articulation of this organ to produce speech, but it is also one of the muscles involved in deglutition (swallowing) of food, a vital reflex action whose center is located in the medulla oblongata.

Innervation and Blood Supply

The genioglossus muscle is innervated by the hypoglossal nerve and is supplied by collateral branches of the lingual artery, which arises from the external carotid artery.

Below, right side of the human face, showing the genioglossus and other extrinsic muscles of the tongue.

Hyoglossus Muscle

The hyoglossus muscle is a paired extrinsic muscle of the human tongue. Flat and rectangular in shape, it is located laterally of the genioglossus, at the base and under this organ of speech.

The hyoglossus originates from the superior border of the body and the greater horn of the hyoid bone. Then its fibers travel upwards and anteriorly towards the lateral margins of the root and body of the tongue, where they run between the styloglossus and  inferior longitudinal muscle, some reaching the tip of the tongue.

Action

The hyoglossus muscle pulls the tongue backwards and downwards, especially when we swallow our food.

Innervation and Blood Supply

It is innervated by the hypoglossal nerve (XII CN) and it receives oxygenated blood from the suprahyoid artery (a branch of the lingual a.) and secondary branches of facial artery, both of which arise from the external carotid artery.

Below, two pictures of human tongue and face, showing the hyoglossus and other extrinsic muscles of this organ.

Styloglossus Muscle

The styloglossus muscle is one of the four extrinsic muscles of the human tongue. It arises from the styloid process and the stylohyoid ligament. Then it travels down obliquely and anteriorly, between the stylohyoid muscle and the pharynx. As it descends, it adjoins the lateral surface of root of tongue and the upper lateral surface of the hyoglossus muscle.

The thicker upper bundle of the styloglossus runs along the lateral margin of the tongue, all the way forward to its tip. Meanwhile, its thinner lower bundle penetrates the hyoglossus muscle and passes downward at the posterior part of tongue to interlace with the tendinous band of its contralateral muscle. This happens on both lateral sides of tongue, as it is a paired muscle.

Action/Function

The styloglossus muscle pulls the tongue backwards and upwards.

Innervation and blood supply 

It is innervated by the hypoglossal nerve and it is supplied with oxygen-rich blood by the sublingual artery, which is a small branch of the lingual.

Down below, illustrative image showing the location of styloglossus in relation to the other muscles of tongue.

Muscles Involved in Jumping

There are several muscles involved in jumping. They are among the largest, longest, and most powerful skeletal muscles of the human body. Also involved in sprinting, they are located in the pelvis, thigh, and leg regions. They are often used by soccer and basketball players when they leap or spring. According to their importance when performing this action, they are:

1) triceps surae, which is a muscle group made up of the gastrocnemius, which consists of two heads, and the soleus muscle, both sharing the same tendon: the Achilles tendon, that is inserted into the calcaneum bone. Action: plantar flexion, raising the body upwards when we stand on tiptoe, and off the ground at the moment of jumping. Innervation: tibial nerve (from sacral plexus);

2) quadriceps femoris, which is a group made up of four muscles (rectus femoris, vastus lateralis, vastus medialis and vastus intermedius); action: they prop up the full weight of the body when we flex the knee just before jumping high, extending the leg at the knee-joint at the moment of jumping. Innervation: femoral nerve (from lumbar plexus);

3) gluteus maximus, which arises from the back of pelvis (ilium) and is inserted in posterior side of proximal portion of femur; action: it extends the thigh, pulling the femur backwards when running and jumping. Innervation: inferior gluteal nerve (from sacral plexus);

4) posterior group of thigh muscles: semitendinosus, semimembranosus, and biceps femoris. Action: they extend the thigh at the hip-joint, flexing the leg at the knee-joint. Innervation: branches of the sciatic nerve (from L4-S3 of lumbo-sacral plexus).

Below, the triceps surae group: the gastrocnemius extending superficialis over the soleus.